assimp/code/FBXConverter.cpp

/*
Open Asset Import Library (assimp)
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/** @file  FBXConverter.cpp
 *  @brief Implementation of the FBX DOM -> aiScene converter
 */

#ifndef ASSIMP_BUILD_NO_FBX_IMPORTER

#include <iterator>
#include <sstream>
#include <boost/tuple/tuple.hpp>
#include <vector>
#include "FBXParser.h"
#include "FBXConverter.h"
#include "FBXDocument.h"
#include "FBXUtil.h"
#include "FBXProperties.h"
#include "FBXImporter.h"
#include "../include/assimp/scene.h"
#include <boost/foreach.hpp>
#include <boost/scoped_array.hpp>


namespace Assimp {
namespace FBX {

    using namespace Util;


#define MAGIC_NODE_TAG "_$AssimpFbx$"

#define CONVERT_FBX_TIME(time) static_cast<double>(time) / 46186158000L

    // XXX vc9's debugger won't step into anonymous namespaces
//namespace {

/** Dummy class to encapsulate the conversion process */
class Converter
{
public:

    /** the different parts that make up the final local transformation of a fbx node */
    enum TransformationComp
    {
        TransformationComp_Translation = 0,
        TransformationComp_RotationOffset,
        TransformationComp_RotationPivot,
        TransformationComp_PreRotation,
        TransformationComp_Rotation,
        TransformationComp_PostRotation,
        TransformationComp_RotationPivotInverse,
        TransformationComp_ScalingOffset,
        TransformationComp_ScalingPivot,
        TransformationComp_Scaling,
        TransformationComp_ScalingPivotInverse,
        TransformationComp_GeometricTranslation,
        TransformationComp_GeometricRotation,
        TransformationComp_GeometricScaling,

        TransformationComp_MAXIMUM
    };

public:

    Converter(aiScene* out, const Document& doc)
        : defaultMaterialIndex()
        , out(out)
        , doc(doc)
    {
        // animations need to be converted first since this will
        // populate the node_anim_chain_bits map, which is needed
        // to determine which nodes need to be generated.
        ConvertAnimations();
        ConvertRootNode();

        if(doc.Settings().readAllMaterials) {
            // unfortunately this means we have to evaluate all objects
            BOOST_FOREACH(const ObjectMap::value_type& v,doc.Objects()) {

                const Object* ob = v.second->Get();
                if(!ob) {
                    continue;
                }

                const Material* mat = dynamic_cast<const Material*>(ob);
                if(mat) {

                    if (materials_converted.find(mat) == materials_converted.end()) {
                        ConvertMaterial(*mat, 0);
                    }
                }
            }
        }

        TransferDataToScene();

        // if we didn't read any meshes set the AI_SCENE_FLAGS_INCOMPLETE
        // to make sure the scene passes assimp's validation. FBX files
        // need not contain geometry (i.e. camera animations, raw armatures).
        if (out->mNumMeshes == 0) {
            out->mFlags |= AI_SCENE_FLAGS_INCOMPLETE;
        }
    }


    ~Converter()
    {
        std::for_each(meshes.begin(),meshes.end(),Util::delete_fun<aiMesh>());
        std::for_each(materials.begin(),materials.end(),Util::delete_fun<aiMaterial>());
        std::for_each(animations.begin(),animations.end(),Util::delete_fun<aiAnimation>());
        std::for_each(lights.begin(),lights.end(),Util::delete_fun<aiLight>());
        std::for_each(cameras.begin(),cameras.end(),Util::delete_fun<aiCamera>());
    }


private:

    // ------------------------------------------------------------------------------------------------
    // find scene root and trigger recursive scene conversion
    void ConvertRootNode()
    {
        out->mRootNode = new aiNode();
        out->mRootNode->mName.Set("RootNode");

        // root has ID 0
        ConvertNodes(0L, *out->mRootNode);
    }


    // ------------------------------------------------------------------------------------------------
    // collect and assign child nodes
    void ConvertNodes(uint64_t id, aiNode& parent, const aiMatrix4x4& parent_transform = aiMatrix4x4())
    {
        const std::vector<const Connection*>& conns = doc.GetConnectionsByDestinationSequenced(id, "Model");

        std::vector<aiNode*> nodes;
        nodes.reserve(conns.size());

        std::vector<aiNode*> nodes_chain;

        try {
            BOOST_FOREACH(const Connection* con, conns) {

                // ignore object-property links
                if(con->PropertyName().length()) {
                    continue;
                }

                const Object* const object = con->SourceObject();
                if(!object) {
                    FBXImporter::LogWarn("failed to convert source object for Model link");
                    continue;
                }

                const Model* const model = dynamic_cast<const Model*>(object);

                if(model) {
                    nodes_chain.clear();

                    aiMatrix4x4 new_abs_transform = parent_transform;

                    // even though there is only a single input node, the design of
                    // assimp (or rather: the complicated transformation chain that
                    // is employed by fbx) means that we may need multiple aiNode's
                    // to represent a fbx node's transformation.
                    GenerateTransformationNodeChain(*model,nodes_chain);

                    ai_assert(nodes_chain.size());

                    const std::string& original_name = FixNodeName(model->Name());

                    // check if any of the nodes in the chain has the name the fbx node
                    // is supposed to have. If there is none, add another node to
                    // preserve the name - people might have scripts etc. that rely
                    // on specific node names.
                    aiNode* name_carrier = NULL;
                    BOOST_FOREACH(aiNode* prenode, nodes_chain) {
                        if ( !strcmp(prenode->mName.C_Str(), original_name.c_str()) ) {
                            name_carrier = prenode;
                            break;
                        }
                    }

                    if(!name_carrier) {
                        nodes_chain.push_back(new aiNode(original_name));
                        name_carrier = nodes_chain.back();
                    }

                    //setup metadata on newest node
                    SetupNodeMetadata(*model, *nodes_chain.back());

                    // link all nodes in a row
                    aiNode* last_parent = &parent;
                    BOOST_FOREACH(aiNode* prenode, nodes_chain) {
                        ai_assert(prenode);

                        if(last_parent != &parent) {
                            last_parent->mNumChildren = 1;
                            last_parent->mChildren = new aiNode*[1];
                            last_parent->mChildren[0] = prenode;
                        }

                        prenode->mParent = last_parent;
                        last_parent = prenode;

                        new_abs_transform *= prenode->mTransformation;
                    }

                    // attach geometry
                    ConvertModel(*model, *nodes_chain.back(), new_abs_transform);

                    // attach sub-nodes
                    ConvertNodes(model->ID(), *nodes_chain.back(), new_abs_transform);

                    if(doc.Settings().readLights) {
                        ConvertLights(*model);
                    }

                    if(doc.Settings().readCameras) {
                        ConvertCameras(*model);
                    }

                    nodes.push_back(nodes_chain.front());
                    nodes_chain.clear();
                }
            }

            if(nodes.size()) {
                parent.mChildren = new aiNode*[nodes.size()]();
                parent.mNumChildren = static_cast<unsigned int>(nodes.size());

                std::swap_ranges(nodes.begin(),nodes.end(),parent.mChildren);
            }
        }
        catch(std::exception&)  {
            Util::delete_fun<aiNode> deleter;
            std::for_each(nodes.begin(),nodes.end(),deleter);
            std::for_each(nodes_chain.begin(),nodes_chain.end(),deleter);
        }
    }


    // ------------------------------------------------------------------------------------------------
    void ConvertLights(const Model& model)
    {
        const std::vector<const NodeAttribute*>& node_attrs = model.GetAttributes();
        BOOST_FOREACH(const NodeAttribute* attr, node_attrs) {
            const Light* const light = dynamic_cast<const Light*>(attr);
            if(light) {
                ConvertLight(model, *light);
            }
        }
    }


    // ------------------------------------------------------------------------------------------------
    void ConvertCameras(const Model& model)
    {
        const std::vector<const NodeAttribute*>& node_attrs = model.GetAttributes();
        BOOST_FOREACH(const NodeAttribute* attr, node_attrs) {
            const Camera* const cam = dynamic_cast<const Camera*>(attr);
            if(cam) {
                ConvertCamera(model, *cam);
            }
        }
    }


    // ------------------------------------------------------------------------------------------------
    void ConvertLight(const Model& model, const Light& light)
    {
        lights.push_back(new aiLight());
        aiLight* const out_light = lights.back();

        out_light->mName.Set(FixNodeName(model.Name()));

        const float intensity = light.Intensity();
        const aiVector3D& col = light.Color();

        out_light->mColorDiffuse = aiColor3D(col.x,col.y,col.z);
        out_light->mColorDiffuse.r *= intensity;
        out_light->mColorDiffuse.g *= intensity;
        out_light->mColorDiffuse.b *= intensity;

        out_light->mColorSpecular = out_light->mColorDiffuse;

        switch(light.LightType())
        {
        case Light::Type_Point:
            out_light->mType = aiLightSource_POINT;
            break;

        case Light::Type_Directional:
            out_light->mType = aiLightSource_DIRECTIONAL;
            break;

        case Light::Type_Spot:
            out_light->mType = aiLightSource_SPOT;
            out_light->mAngleOuterCone = AI_DEG_TO_RAD(light.OuterAngle());
            out_light->mAngleInnerCone = AI_DEG_TO_RAD(light.InnerAngle());
            break;

        case Light::Type_Area:
            FBXImporter::LogWarn("cannot represent area light, set to UNDEFINED");
            out_light->mType = aiLightSource_UNDEFINED;
            break;

        case Light::Type_Volume:
            FBXImporter::LogWarn("cannot represent volume light, set to UNDEFINED");
            out_light->mType = aiLightSource_UNDEFINED;
            break;
        default:
            ai_assert(false);
        }

        // XXX: how to best convert the near and far decay ranges?
        switch(light.DecayType())
        {
        case Light::Decay_None:
            out_light->mAttenuationConstant = 1.0f;
            break;
        case Light::Decay_Linear:
            out_light->mAttenuationLinear = 1.0f;
            break;
        case Light::Decay_Quadratic:
            out_light->mAttenuationQuadratic = 1.0f;
            break;
        case Light::Decay_Cubic:
            FBXImporter::LogWarn("cannot represent cubic attenuation, set to Quadratic");
            out_light->mAttenuationQuadratic = 1.0f;
            break;
        default:
            ai_assert(false);
        }
    }


    // ------------------------------------------------------------------------------------------------
    void ConvertCamera(const Model& model, const Camera& cam)
    {
        cameras.push_back(new aiCamera());
        aiCamera* const out_camera = cameras.back();

        out_camera->mName.Set(FixNodeName(model.Name()));

        out_camera->mAspect = cam.AspectWidth() / cam.AspectHeight();
        out_camera->mPosition = cam.Position();
        out_camera->mLookAt = cam.InterestPosition() - out_camera->mPosition;
        out_camera->mHorizontalFOV = AI_DEG_TO_RAD(cam.FieldOfView());
    }


    // ------------------------------------------------------------------------------------------------
    // this returns unified names usable within assimp identifiers (i.e. no space characters -
    // while these would be allowed, they are a potential trouble spot so better not use them).
    const char* NameTransformationComp(TransformationComp comp)
    {
        switch(comp)
        {
        case TransformationComp_Translation:
            return "Translation";
        case TransformationComp_RotationOffset:
            return "RotationOffset";
        case TransformationComp_RotationPivot:
            return "RotationPivot";
        case TransformationComp_PreRotation:
            return "PreRotation";
        case TransformationComp_Rotation:
            return "Rotation";
        case TransformationComp_PostRotation:
            return "PostRotation";
        case TransformationComp_RotationPivotInverse:
            return "RotationPivotInverse";
        case TransformationComp_ScalingOffset:
            return "ScalingOffset";
        case TransformationComp_ScalingPivot:
            return "ScalingPivot";
        case TransformationComp_Scaling:
            return "Scaling";
        case TransformationComp_ScalingPivotInverse:
            return "ScalingPivotInverse";
        case TransformationComp_GeometricScaling:
            return "GeometricScaling";
        case TransformationComp_GeometricRotation:
            return "GeometricRotation";
        case TransformationComp_GeometricTranslation:
            return "GeometricTranslation";
        case TransformationComp_MAXIMUM: // this is to silence compiler warnings
            break;
        }

        ai_assert(false);
        return NULL;
    }


    // ------------------------------------------------------------------------------------------------
    // note: this returns the REAL fbx property names
    const char* NameTransformationCompProperty(TransformationComp comp)
    {
        switch(comp)
        {
        case TransformationComp_Translation:
            return "Lcl Translation";
        case TransformationComp_RotationOffset:
            return "RotationOffset";
        case TransformationComp_RotationPivot:
            return "RotationPivot";
        case TransformationComp_PreRotation:
            return "PreRotation";
        case TransformationComp_Rotation:
            return "Lcl Rotation";
        case TransformationComp_PostRotation:
            return "PostRotation";
        case TransformationComp_RotationPivotInverse:
            return "RotationPivotInverse";
        case TransformationComp_ScalingOffset:
            return "ScalingOffset";
        case TransformationComp_ScalingPivot:
            return "ScalingPivot";
        case TransformationComp_Scaling:
            return "Lcl Scaling";
        case TransformationComp_ScalingPivotInverse:
            return "ScalingPivotInverse";
        case TransformationComp_GeometricScaling:
            return "GeometricScaling";
        case TransformationComp_GeometricRotation:
            return "GeometricRotation";
        case TransformationComp_GeometricTranslation:
            return "GeometricTranslation";
        case TransformationComp_MAXIMUM: // this is to silence compiler warnings
            break;
        }

        ai_assert(false);
        return NULL;
    }


    // ------------------------------------------------------------------------------------------------
    aiVector3D TransformationCompDefaultValue(TransformationComp comp)
    {
        // XXX a neat way to solve the never-ending special cases for scaling
        // would be to do everything in log space!
        return comp == TransformationComp_Scaling ? aiVector3D(1.f,1.f,1.f) : aiVector3D();
    }


    // ------------------------------------------------------------------------------------------------
    void GetRotationMatrix(Model::RotOrder mode, const aiVector3D& rotation, aiMatrix4x4& out)
    {
        if(mode == Model::RotOrder_SphericXYZ) {
            FBXImporter::LogError("Unsupported RotationMode: SphericXYZ");
            out = aiMatrix4x4();
            return;
        }

        const float angle_epsilon = 1e-6f;

        out = aiMatrix4x4();

        bool is_id[3] = { true, true, true };

        aiMatrix4x4 temp[3];
        if(std::fabs(rotation.z) > angle_epsilon) {
            aiMatrix4x4::RotationZ(AI_DEG_TO_RAD(rotation.z),temp[2]);
            is_id[2] = false;
        }
        if(std::fabs(rotation.y) > angle_epsilon) {
            aiMatrix4x4::RotationY(AI_DEG_TO_RAD(rotation.y),temp[1]);
            is_id[1] = false;
        }
        if(std::fabs(rotation.x) > angle_epsilon) {
            aiMatrix4x4::RotationX(AI_DEG_TO_RAD(rotation.x),temp[0]);
            is_id[0] = false;
        }

        int order[3] = {-1, -1, -1};

        // note: rotation order is inverted since we're left multiplying as is usual in assimp
        switch(mode)
        {
        case Model::RotOrder_EulerXYZ:
            order[0] = 2;
            order[1] = 1;
            order[2] = 0;
            break;

        case Model::RotOrder_EulerXZY:
            order[0] = 1;
            order[1] = 2;
            order[2] = 0;
            break;

        case Model::RotOrder_EulerYZX:
            order[0] = 0;
            order[1] = 2;
            order[2] = 1;
            break;

        case Model::RotOrder_EulerYXZ:
            order[0] = 2;
            order[1] = 0;
            order[2] = 1;
            break;

        case Model::RotOrder_EulerZXY:
            order[0] = 1;
            order[1] = 0;
            order[2] = 2;
            break;

        case Model::RotOrder_EulerZYX:
            order[0] = 0;
            order[1] = 1;
            order[2] = 2;
            break;

            default:
                ai_assert(false);
        }

        ai_assert((order[0] >= 0) && (order[0] <= 2));
        ai_assert((order[1] >= 0) && (order[1] <= 2));
        ai_assert((order[2] >= 0) && (order[2] <= 2));

        if(!is_id[order[0]]) {
            out = temp[order[0]];
        }

        if(!is_id[order[1]]) {
            out = out * temp[order[1]];
        }

        if(!is_id[order[2]]) {
            out = out * temp[order[2]];
        }
    }


    // ------------------------------------------------------------------------------------------------
    /** checks if a node has more than just scaling, rotation and translation components */
    bool NeedsComplexTransformationChain(const Model& model)
    {
        const PropertyTable& props = model.Props();
        bool ok;

        const float zero_epsilon = 1e-6f;
        for (size_t i = 0; i < TransformationComp_MAXIMUM; ++i) {
            const TransformationComp comp = static_cast<TransformationComp>(i);

            if( comp == TransformationComp_Rotation || comp == TransformationComp_Scaling || comp == TransformationComp_Translation ||
                comp == TransformationComp_GeometricScaling || comp == TransformationComp_GeometricRotation || comp == TransformationComp_GeometricTranslation ) {
                continue;
            }

            const aiVector3D& v = PropertyGet<aiVector3D>(props,NameTransformationCompProperty(comp),ok);
            if(ok && v.SquareLength() > zero_epsilon) {
                return true;
            }
        }

        return false;
    }


    // ------------------------------------------------------------------------------------------------
    // note: name must be a FixNodeName() result
    std::string NameTransformationChainNode(const std::string& name, TransformationComp comp)
    {
        return name + std::string(MAGIC_NODE_TAG) + "_" + NameTransformationComp(comp);
    }


    // ------------------------------------------------------------------------------------------------
    /** note: memory for output_nodes will be managed by the caller */
    void GenerateTransformationNodeChain(const Model& model,
        std::vector<aiNode*>& output_nodes)
    {
        const PropertyTable& props = model.Props();
        const Model::RotOrder rot = model.RotationOrder();

        bool ok;

        aiMatrix4x4 chain[TransformationComp_MAXIMUM];
        std::fill_n(chain, static_cast<unsigned int>(TransformationComp_MAXIMUM), aiMatrix4x4());

        // generate transformation matrices for all the different transformation components
        const float zero_epsilon = 1e-6f;
        bool is_complex = false;

        const aiVector3D& PreRotation = PropertyGet<aiVector3D>(props,"PreRotation",ok);
        if(ok && PreRotation.SquareLength() > zero_epsilon) {
            is_complex = true;

            GetRotationMatrix(rot, PreRotation, chain[TransformationComp_PreRotation]);
        }

        const aiVector3D& PostRotation = PropertyGet<aiVector3D>(props,"PostRotation",ok);
        if(ok && PostRotation.SquareLength() > zero_epsilon) {
            is_complex = true;

            GetRotationMatrix(rot, PostRotation, chain[TransformationComp_PostRotation]);
        }

        const aiVector3D& RotationPivot = PropertyGet<aiVector3D>(props,"RotationPivot",ok);
        if(ok && RotationPivot.SquareLength() > zero_epsilon) {
            is_complex = true;

            aiMatrix4x4::Translation(RotationPivot,chain[TransformationComp_RotationPivot]);
            aiMatrix4x4::Translation(-RotationPivot,chain[TransformationComp_RotationPivotInverse]);
        }

        const aiVector3D& RotationOffset = PropertyGet<aiVector3D>(props,"RotationOffset",ok);
        if(ok && RotationOffset.SquareLength() > zero_epsilon) {
            is_complex = true;

            aiMatrix4x4::Translation(RotationOffset,chain[TransformationComp_RotationOffset]);
        }

        const aiVector3D& ScalingOffset = PropertyGet<aiVector3D>(props,"ScalingOffset",ok);
        if(ok && ScalingOffset.SquareLength() > zero_epsilon) {
            is_complex = true;

            aiMatrix4x4::Translation(ScalingOffset,chain[TransformationComp_ScalingOffset]);
        }

        const aiVector3D& ScalingPivot = PropertyGet<aiVector3D>(props,"ScalingPivot",ok);
        if(ok && ScalingPivot.SquareLength() > zero_epsilon) {
            is_complex = true;

            aiMatrix4x4::Translation(ScalingPivot,chain[TransformationComp_ScalingPivot]);
            aiMatrix4x4::Translation(-ScalingPivot,chain[TransformationComp_ScalingPivotInverse]);
        }

        const aiVector3D& Translation = PropertyGet<aiVector3D>(props,"Lcl Translation",ok);
        if(ok && Translation.SquareLength() > zero_epsilon) {
            aiMatrix4x4::Translation(Translation,chain[TransformationComp_Translation]);
        }

        const aiVector3D& Scaling = PropertyGet<aiVector3D>(props,"Lcl Scaling",ok);
        if(ok && std::fabs(Scaling.SquareLength()-1.0f) > zero_epsilon) {
            aiMatrix4x4::Scaling(Scaling,chain[TransformationComp_Scaling]);
        }

        const aiVector3D& Rotation = PropertyGet<aiVector3D>(props,"Lcl Rotation",ok);
        if(ok && Rotation.SquareLength() > zero_epsilon) {
            GetRotationMatrix(rot, Rotation, chain[TransformationComp_Rotation]);
        }

        const aiVector3D& GeometricScaling = PropertyGet<aiVector3D>(props, "GeometricScaling", ok);
        if (ok && std::fabs(GeometricScaling.SquareLength() - 1.0f) > zero_epsilon) {
            aiMatrix4x4::Scaling(GeometricScaling, chain[TransformationComp_GeometricScaling]);
        }

        const aiVector3D& GeometricRotation = PropertyGet<aiVector3D>(props, "GeometricRotation", ok);
        if (ok && GeometricRotation.SquareLength() > zero_epsilon) {
            GetRotationMatrix(rot, GeometricRotation, chain[TransformationComp_GeometricRotation]);
        }

        const aiVector3D& GeometricTranslation = PropertyGet<aiVector3D>(props, "GeometricTranslation", ok);
        if (ok && GeometricTranslation.SquareLength() > zero_epsilon){
            aiMatrix4x4::Translation(GeometricTranslation, chain[TransformationComp_GeometricTranslation]);
        }

        // is_complex needs to be consistent with NeedsComplexTransformationChain()
        // or the interplay between this code and the animation converter would
        // not be guaranteed.
        ai_assert(NeedsComplexTransformationChain(model) == is_complex);

        const std::string& name = FixNodeName(model.Name());

        // now, if we have more than just Translation, Scaling and Rotation,
        // we need to generate a full node chain to accommodate for assimp's
        // lack to express pivots and offsets.
        if(is_complex && doc.Settings().preservePivots) {
            FBXImporter::LogInfo("generating full transformation chain for node: " + name);

            // query the anim_chain_bits dictionary to find out which chain elements
            // have associated node animation channels. These can not be dropped
            // even if they have identity transform in bind pose.
            NodeAnimBitMap::const_iterator it = node_anim_chain_bits.find(name);
            const unsigned int anim_chain_bitmask = (it == node_anim_chain_bits.end() ? 0 : (*it).second);

            unsigned int bit = 0x1;
            for (size_t i = 0; i < TransformationComp_MAXIMUM; ++i, bit <<= 1) {
                const TransformationComp comp = static_cast<TransformationComp>(i);

                if (chain[i].IsIdentity() && (anim_chain_bitmask & bit) == 0) {
                    continue;
                }

                aiNode* nd = new aiNode();
                output_nodes.push_back(nd);

                nd->mName.Set(NameTransformationChainNode(name, comp));
                nd->mTransformation = chain[i];
            }

            ai_assert(output_nodes.size());
            return;
        }

        // else, we can just multiply the matrices together
        aiNode* nd = new aiNode();
        output_nodes.push_back(nd);

        nd->mName.Set(name);

        for (size_t i = 0; i < TransformationComp_MAXIMUM; ++i) {
            nd->mTransformation = nd->mTransformation * chain[i];
        }
    }

    // ------------------------------------------------------------------------------------------------

    void SetupNodeMetadata(const Model& model, aiNode& nd)
    {
        const PropertyTable& props = model.Props();
        DirectPropertyMap unparsedProperties = props.GetUnparsedProperties();

        // create metadata on node
        std::size_t numStaticMetaData = 2;
        aiMetadata* data = new aiMetadata();
        data->mNumProperties = unparsedProperties.size() + numStaticMetaData;
        data->mKeys = new aiString[data->mNumProperties]();
        data->mValues = new aiMetadataEntry[data->mNumProperties]();
        nd.mMetaData = data;
        int index = 0;

        // find user defined properties (3ds Max)
        data->Set(index++, "UserProperties", aiString(PropertyGet<std::string>(props, "UDP3DSMAX", "")));
        // preserve the info that a node was marked as Null node in the original file.
        data->Set(index++, "IsNull", model.IsNull() ? true : false);

        // add unparsed properties to the node's metadata
        BOOST_FOREACH(const DirectPropertyMap::value_type& prop, unparsedProperties) {

            // Interpret the property as a concrete type
            if (const TypedProperty<bool>* interpreted = prop.second->As<TypedProperty<bool> >())
                data->Set(index++, prop.first, interpreted->Value());
            else if (const TypedProperty<int>* interpreted = prop.second->As<TypedProperty<int> >())
                data->Set(index++, prop.first, interpreted->Value());
            else if (const TypedProperty<uint64_t>* interpreted = prop.second->As<TypedProperty<uint64_t> >())
                data->Set(index++, prop.first, interpreted->Value());
            else if (const TypedProperty<float>* interpreted = prop.second->As<TypedProperty<float> >())
                data->Set(index++, prop.first, interpreted->Value());
            else if (const TypedProperty<std::string>* interpreted = prop.second->As<TypedProperty<std::string> >())
                data->Set(index++, prop.first, aiString(interpreted->Value()));
            else if (const TypedProperty<aiVector3D>* interpreted = prop.second->As<TypedProperty<aiVector3D> >())
                data->Set(index++, prop.first, interpreted->Value());
            else
                assert(false);
        }
    }

    // ------------------------------------------------------------------------------------------------
    void ConvertModel(const Model& model, aiNode& nd, const aiMatrix4x4& node_global_transform)
    {
        const std::vector<const Geometry*>& geos = model.GetGeometry();

        std::vector<unsigned int> meshes;
        meshes.reserve(geos.size());

        BOOST_FOREACH(const Geometry* geo, geos) {

            const MeshGeometry* const mesh = dynamic_cast<const MeshGeometry*>(geo);
            if(mesh) {
                const std::vector<unsigned int>& indices = ConvertMesh(*mesh, model, node_global_transform);
                std::copy(indices.begin(),indices.end(),std::back_inserter(meshes) );
            }
            else {
                FBXImporter::LogWarn("ignoring unrecognized geometry: " + geo->Name());
            }
        }

        if(meshes.size()) {
            nd.mMeshes = new unsigned int[meshes.size()]();
            nd.mNumMeshes = static_cast<unsigned int>(meshes.size());

            std::swap_ranges(meshes.begin(),meshes.end(),nd.mMeshes);
        }
    }


    // ------------------------------------------------------------------------------------------------
    // MeshGeometry -> aiMesh, return mesh index + 1 or 0 if the conversion failed
    std::vector<unsigned int> ConvertMesh(const MeshGeometry& mesh,const Model& model,
        const aiMatrix4x4& node_global_transform)
    {
        std::vector<unsigned int> temp;

        MeshMap::const_iterator it = meshes_converted.find(&mesh);
        if (it != meshes_converted.end()) {
            std::copy((*it).second.begin(),(*it).second.end(),std::back_inserter(temp));
            return temp;
        }

        const std::vector<aiVector3D>& vertices = mesh.GetVertices();
        const std::vector<unsigned int>& faces = mesh.GetFaceIndexCounts();
        if(vertices.empty() || faces.empty()) {
            FBXImporter::LogWarn("ignoring empty geometry: " + mesh.Name());
            return temp;
        }

        // one material per mesh maps easily to aiMesh. Multiple material
        // meshes need to be split.
        const MatIndexArray& mindices = mesh.GetMaterialIndices();
        if (doc.Settings().readMaterials && !mindices.empty()) {
            const MatIndexArray::value_type base = mindices[0];
            BOOST_FOREACH(MatIndexArray::value_type index, mindices) {
                if(index != base) {
                    return ConvertMeshMultiMaterial(mesh, model, node_global_transform);
                }
            }
        }

        // faster codepath, just copy the data
        temp.push_back(ConvertMeshSingleMaterial(mesh, model, node_global_transform));
        return temp;
    }


    // ------------------------------------------------------------------------------------------------
    aiMesh* SetupEmptyMesh(const MeshGeometry& mesh)
    {
        aiMesh* const out_mesh = new aiMesh();
        meshes.push_back(out_mesh);
        meshes_converted[&mesh].push_back(static_cast<unsigned int>(meshes.size()-1));

        // set name
        std::string name = mesh.Name();
        if (name.substr(0,10) == "Geometry::") {
            name = name.substr(10);
        }

        if(name.length()) {
            out_mesh->mName.Set(name);
        }

        return out_mesh;
    }


    // ------------------------------------------------------------------------------------------------
    unsigned int ConvertMeshSingleMaterial(const MeshGeometry& mesh, const Model& model,
        const aiMatrix4x4& node_global_transform)
    {
        const MatIndexArray& mindices = mesh.GetMaterialIndices();
        aiMesh* const out_mesh = SetupEmptyMesh(mesh);

        const std::vector<aiVector3D>& vertices = mesh.GetVertices();
        const std::vector<unsigned int>& faces = mesh.GetFaceIndexCounts();

        // copy vertices
        out_mesh->mNumVertices = static_cast<unsigned int>(vertices.size());
        out_mesh->mVertices = new aiVector3D[vertices.size()];
        std::copy(vertices.begin(),vertices.end(),out_mesh->mVertices);

        // generate dummy faces
        out_mesh->mNumFaces = static_cast<unsigned int>(faces.size());
        aiFace* fac = out_mesh->mFaces = new aiFace[faces.size()]();

        unsigned int cursor = 0;
        BOOST_FOREACH(unsigned int pcount, faces) {
            aiFace& f = *fac++;
            f.mNumIndices = pcount;
            f.mIndices = new unsigned int[pcount];
            switch(pcount)
            {
            case 1:
                out_mesh->mPrimitiveTypes |= aiPrimitiveType_POINT;
                break;
            case 2:
                out_mesh->mPrimitiveTypes |= aiPrimitiveType_LINE;
                break;
            case 3:
                out_mesh->mPrimitiveTypes |= aiPrimitiveType_TRIANGLE;
                break;
            default:
                out_mesh->mPrimitiveTypes |= aiPrimitiveType_POLYGON;
                break;
            }
            for (unsigned int i = 0; i < pcount; ++i) {
                f.mIndices[i] = cursor++;
            }
        }

        // copy normals
        const std::vector<aiVector3D>& normals = mesh.GetNormals();
        if(normals.size()) {
            ai_assert(normals.size() == vertices.size());

            out_mesh->mNormals = new aiVector3D[vertices.size()];
            std::copy(normals.begin(),normals.end(),out_mesh->mNormals);
        }

        // copy tangents - assimp requires both tangents and bitangents (binormals)
        // to be present, or neither of them. Compute binormals from normals
        // and tangents if needed.
        const std::vector<aiVector3D>& tangents = mesh.GetTangents();
        const std::vector<aiVector3D>* binormals = &mesh.GetBinormals();

        if(tangents.size()) {
            std::vector<aiVector3D> tempBinormals;
            if (!binormals->size()) {
                if (normals.size()) {
                    tempBinormals.resize(normals.size());
                    for (unsigned int i = 0; i < tangents.size(); ++i) {
                        tempBinormals[i] = normals[i] ^ tangents[i];
                    }

                    binormals = &tempBinormals;
                }
                else {
                    binormals = NULL;
                }
            }

            if(binormals) {
                ai_assert(tangents.size() == vertices.size() && binormals->size() == vertices.size());

                out_mesh->mTangents = new aiVector3D[vertices.size()];
                std::copy(tangents.begin(),tangents.end(),out_mesh->mTangents);

                out_mesh->mBitangents = new aiVector3D[vertices.size()];
                std::copy(binormals->begin(),binormals->end(),out_mesh->mBitangents);
            }
        }

        // copy texture coords
        for (unsigned int i = 0; i < AI_MAX_NUMBER_OF_TEXTURECOORDS; ++i) {
            const std::vector<aiVector2D>& uvs = mesh.GetTextureCoords(i);
            if(uvs.empty()) {
                break;
            }

            aiVector3D* out_uv = out_mesh->mTextureCoords[i] = new aiVector3D[vertices.size()];
            BOOST_FOREACH(const aiVector2D& v, uvs) {
                *out_uv++ = aiVector3D(v.x,v.y,0.0f);
            }

            out_mesh->mNumUVComponents[i] = 2;
        }

        // copy vertex colors
        for (unsigned int i = 0; i < AI_MAX_NUMBER_OF_COLOR_SETS; ++i) {
            const std::vector<aiColor4D>& colors = mesh.GetVertexColors(i);
            if(colors.empty()) {
                break;
            }

            out_mesh->mColors[i] = new aiColor4D[vertices.size()];
            std::copy(colors.begin(),colors.end(),out_mesh->mColors[i]);
        }

        if(!doc.Settings().readMaterials || mindices.empty()) {
            FBXImporter::LogError("no material assigned to mesh, setting default material");
            out_mesh->mMaterialIndex = GetDefaultMaterial();
        }
        else {
            ConvertMaterialForMesh(out_mesh,model,mesh,mindices[0]);
        }

        if(doc.Settings().readWeights && mesh.DeformerSkin() != NULL) {
            ConvertWeights(out_mesh, model, mesh, node_global_transform, NO_MATERIAL_SEPARATION);
        }

        return static_cast<unsigned int>(meshes.size() - 1);
    }


    // ------------------------------------------------------------------------------------------------
    std::vector<unsigned int> ConvertMeshMultiMaterial(const MeshGeometry& mesh, const Model& model,
        const aiMatrix4x4& node_global_transform)
    {
        const MatIndexArray& mindices = mesh.GetMaterialIndices();
        ai_assert(mindices.size());

        std::set<MatIndexArray::value_type> had;
        std::vector<unsigned int> indices;

        BOOST_FOREACH(MatIndexArray::value_type index, mindices) {
            if(had.find(index) == had.end()) {

                indices.push_back(ConvertMeshMultiMaterial(mesh, model, index, node_global_transform));
                had.insert(index);
            }
        }

        return indices;
    }


    // ------------------------------------------------------------------------------------------------
    unsigned int ConvertMeshMultiMaterial(const MeshGeometry& mesh, const Model& model,
        MatIndexArray::value_type index,
        const aiMatrix4x4& node_global_transform)
    {
        aiMesh* const out_mesh = SetupEmptyMesh(mesh);

        const MatIndexArray& mindices = mesh.GetMaterialIndices();
        const std::vector<aiVector3D>& vertices = mesh.GetVertices();
        const std::vector<unsigned int>& faces = mesh.GetFaceIndexCounts();

        const bool process_weights = doc.Settings().readWeights && mesh.DeformerSkin() != NULL;

        unsigned int count_faces = 0;
        unsigned int count_vertices = 0;

        // count faces
        std::vector<unsigned int>::const_iterator itf = faces.begin();
        for(MatIndexArray::const_iterator it = mindices.begin(),
            end = mindices.end(); it != end; ++it, ++itf)
        {
            if ((*it) != index) {
                continue;
            }
            ++count_faces;
            count_vertices += *itf;
        }

        ai_assert(count_faces);
        ai_assert(count_vertices);

        // mapping from output indices to DOM indexing, needed to resolve weights
        std::vector<unsigned int> reverseMapping;

        if (process_weights) {
            reverseMapping.resize(count_vertices);
        }

        // allocate output data arrays, but don't fill them yet
        out_mesh->mNumVertices = count_vertices;
        out_mesh->mVertices = new aiVector3D[count_vertices];

        out_mesh->mNumFaces = count_faces;
        aiFace* fac = out_mesh->mFaces = new aiFace[count_faces]();


        // allocate normals
        const std::vector<aiVector3D>& normals = mesh.GetNormals();
        if(normals.size()) {
            ai_assert(normals.size() == vertices.size());
            out_mesh->mNormals = new aiVector3D[vertices.size()];
        }

        // allocate tangents, binormals.
        const std::vector<aiVector3D>& tangents = mesh.GetTangents();
        const std::vector<aiVector3D>* binormals = &mesh.GetBinormals();

        if(tangents.size()) {
            std::vector<aiVector3D> tempBinormals;
            if (!binormals->size()) {
                if (normals.size()) {
                    // XXX this computes the binormals for the entire mesh, not only
                    // the part for which we need them.
                    tempBinormals.resize(normals.size());
                    for (unsigned int i = 0; i < tangents.size(); ++i) {
                        tempBinormals[i] = normals[i] ^ tangents[i];
                    }

                    binormals = &tempBinormals;
                }
                else {
                    binormals = NULL;
                }
            }

            if(binormals) {
                ai_assert(tangents.size() == vertices.size() && binormals->size() == vertices.size());

                out_mesh->mTangents = new aiVector3D[vertices.size()];
                out_mesh->mBitangents = new aiVector3D[vertices.size()];
            }
        }

        // allocate texture coords
        unsigned int num_uvs = 0;
        for (unsigned int i = 0; i < AI_MAX_NUMBER_OF_TEXTURECOORDS; ++i, ++num_uvs) {
            const std::vector<aiVector2D>& uvs = mesh.GetTextureCoords(i);
            if(uvs.empty()) {
                break;
            }

            out_mesh->mTextureCoords[i] = new aiVector3D[vertices.size()];
            out_mesh->mNumUVComponents[i] = 2;
        }

        // allocate vertex colors
        unsigned int num_vcs = 0;
        for (unsigned int i = 0; i < AI_MAX_NUMBER_OF_COLOR_SETS; ++i, ++num_vcs) {
            const std::vector<aiColor4D>& colors = mesh.GetVertexColors(i);
            if(colors.empty()) {
                break;
            }

            out_mesh->mColors[i] = new aiColor4D[vertices.size()];
        }

        unsigned int cursor = 0, in_cursor = 0;

        itf = faces.begin();
        for(MatIndexArray::const_iterator it = mindices.begin(),
            end = mindices.end(); it != end; ++it, ++itf)
        {
            const unsigned int pcount = *itf;
            if ((*it) != index) {
                in_cursor += pcount;
                continue;
            }

            aiFace& f = *fac++;

            f.mNumIndices = pcount;
            f.mIndices = new unsigned int[pcount];
            switch(pcount)
            {
            case 1:
                out_mesh->mPrimitiveTypes |= aiPrimitiveType_POINT;
                break;
            case 2:
                out_mesh->mPrimitiveTypes |= aiPrimitiveType_LINE;
                break;
            case 3:
                out_mesh->mPrimitiveTypes |= aiPrimitiveType_TRIANGLE;
                break;
            default:
                out_mesh->mPrimitiveTypes |= aiPrimitiveType_POLYGON;
                break;
            }
            for (unsigned int i = 0; i < pcount; ++i, ++cursor, ++in_cursor) {
                f.mIndices[i] = cursor;

                if(reverseMapping.size()) {
                    reverseMapping[cursor] = in_cursor;
                }

                out_mesh->mVertices[cursor] = vertices[in_cursor];

                if(out_mesh->mNormals) {
                    out_mesh->mNormals[cursor] = normals[in_cursor];
                }

                if(out_mesh->mTangents) {
                    out_mesh->mTangents[cursor] = tangents[in_cursor];
                    out_mesh->mBitangents[cursor] = (*binormals)[in_cursor];
                }

                for (unsigned int i = 0; i < num_uvs; ++i) {
                    const std::vector<aiVector2D>& uvs = mesh.GetTextureCoords(i);
                    out_mesh->mTextureCoords[i][cursor] = aiVector3D(uvs[in_cursor].x,uvs[in_cursor].y, 0.0f);
                }

                for (unsigned int i = 0; i < num_vcs; ++i) {
                    const std::vector<aiColor4D>& cols = mesh.GetVertexColors(i);
                    out_mesh->mColors[i][cursor] = cols[in_cursor];
                }
            }
        }

        ConvertMaterialForMesh(out_mesh,model,mesh,index);

        if(process_weights) {
            ConvertWeights(out_mesh, model, mesh, node_global_transform, index, &reverseMapping);
        }

        return static_cast<unsigned int>(meshes.size() - 1);
    }

    static const unsigned int NO_MATERIAL_SEPARATION = /* std::numeric_limits<unsigned int>::max() */
        static_cast<unsigned int>(-1);


    // ------------------------------------------------------------------------------------------------
    /** - if materialIndex == NO_MATERIAL_SEPARATION, materials are not taken into
     *  account when determining which weights to include.
     *  - outputVertStartIndices is only used when a material index is specified, it gives for
     *    each output vertex the DOM index it maps to. */
    void ConvertWeights(aiMesh* out, const Model& model, const MeshGeometry& geo,
        const aiMatrix4x4& node_global_transform = aiMatrix4x4(),
        unsigned int materialIndex = NO_MATERIAL_SEPARATION,
        std::vector<unsigned int>* outputVertStartIndices = NULL)
    {
        ai_assert(geo.DeformerSkin());

        std::vector<size_t> out_indices;
        std::vector<size_t> index_out_indices;
        std::vector<size_t> count_out_indices;

        const Skin& sk = *geo.DeformerSkin();

        std::vector<aiBone*> bones;
        bones.reserve(sk.Clusters().size());

        const bool no_mat_check = materialIndex == NO_MATERIAL_SEPARATION;
        ai_assert(no_mat_check || outputVertStartIndices);

        try {

            BOOST_FOREACH(const Cluster* cluster, sk.Clusters()) {
                ai_assert(cluster);

                const WeightIndexArray& indices = cluster->GetIndices();

                if(indices.empty()) {
                    continue;
                }

                const MatIndexArray& mats = geo.GetMaterialIndices();

                bool ok = false;

                const size_t no_index_sentinel = std::numeric_limits<size_t>::max();

                count_out_indices.clear();
                index_out_indices.clear();
                out_indices.clear();

                // now check if *any* of these weights is contained in the output mesh,
                // taking notes so we don't need to do it twice.
                BOOST_FOREACH(WeightIndexArray::value_type index, indices) {

                    unsigned int count = 0;
                    const unsigned int* const out_idx = geo.ToOutputVertexIndex(index, count);
                    // ToOutputVertexIndex only returns NULL if index is out of bounds
                    // which should never happen
                    ai_assert(out_idx != NULL);

                    index_out_indices.push_back(no_index_sentinel);
                    count_out_indices.push_back(0);

                    for(unsigned int i = 0; i < count; ++i) {
                        if (no_mat_check || static_cast<size_t>(mats[geo.FaceForVertexIndex(out_idx[i])]) == materialIndex) {

                            if (index_out_indices.back() == no_index_sentinel) {
                                index_out_indices.back() = out_indices.size();

                            }

                            if (no_mat_check) {
                                out_indices.push_back(out_idx[i]);
                            }
                            else {
                                // this extra lookup is in O(logn), so the entire algorithm becomes O(nlogn)
                                const std::vector<unsigned int>::iterator it = std::lower_bound(
                                    outputVertStartIndices->begin(),
                                    outputVertStartIndices->end(),
                                    out_idx[i]
                                );

                                out_indices.push_back(std::distance(outputVertStartIndices->begin(), it));
                            }

                            ++count_out_indices.back();
                            ok = true;
                        }
                    }
                }

                // if we found at least one, generate the output bones
                // XXX this could be heavily simplified by collecting the bone
                // data in a single step.
                if (ok) {
                    ConvertCluster(bones, model, *cluster, out_indices, index_out_indices,
                        count_out_indices, node_global_transform);
                }
            }
        }
        catch (std::exception&) {
            std::for_each(bones.begin(),bones.end(),Util::delete_fun<aiBone>());
            throw;
        }

        if(bones.empty()) {
            return;
        }

        out->mBones = new aiBone*[bones.size()]();
        out->mNumBones = static_cast<unsigned int>(bones.size());

        std::swap_ranges(bones.begin(),bones.end(),out->mBones);
    }



    // ------------------------------------------------------------------------------------------------
    void ConvertCluster(std::vector<aiBone*>& bones, const Model& /*model*/, const Cluster& cl,
        std::vector<size_t>& out_indices,
        std::vector<size_t>& index_out_indices,
        std::vector<size_t>& count_out_indices,
        const aiMatrix4x4& node_global_transform)
    {

        aiBone* const bone = new aiBone();
        bones.push_back(bone);

        bone->mName = FixNodeName(cl.TargetNode()->Name());

        bone->mOffsetMatrix = cl.TransformLink();
        bone->mOffsetMatrix.Inverse();

        bone->mOffsetMatrix = bone->mOffsetMatrix * node_global_transform;

        bone->mNumWeights = static_cast<unsigned int>(out_indices.size());
        aiVertexWeight* cursor = bone->mWeights = new aiVertexWeight[out_indices.size()];

        const size_t no_index_sentinel = std::numeric_limits<size_t>::max();
        const WeightArray& weights = cl.GetWeights();

        const size_t c = index_out_indices.size();
        for (size_t i = 0; i < c; ++i) {
            const size_t index_index =  index_out_indices[i];

            if (index_index == no_index_sentinel) {
                continue;
            }

            const size_t cc = count_out_indices[i];
            for (size_t j = 0; j < cc; ++j) {
                aiVertexWeight& out_weight = *cursor++;

                out_weight.mVertexId = static_cast<unsigned int>(out_indices[index_index + j]);
                out_weight.mWeight = weights[i];
            }
        }
    }


    // ------------------------------------------------------------------------------------------------
    void ConvertMaterialForMesh(aiMesh* out, const Model& model, const MeshGeometry& geo,
        MatIndexArray::value_type materialIndex)
    {
        // locate source materials for this mesh
        const std::vector<const Material*>& mats = model.GetMaterials();
        if (static_cast<unsigned int>(materialIndex) >= mats.size() || materialIndex < 0) {
            FBXImporter::LogError("material index out of bounds, setting default material");
            out->mMaterialIndex = GetDefaultMaterial();
            return;
        }

        const Material* const mat = mats[materialIndex];
        MaterialMap::const_iterator it = materials_converted.find(mat);
        if (it != materials_converted.end()) {
            out->mMaterialIndex = (*it).second;
            return;
        }

        out->mMaterialIndex = ConvertMaterial(*mat, &geo);
        materials_converted[mat] = out->mMaterialIndex;
    }


    // ------------------------------------------------------------------------------------------------
    unsigned int GetDefaultMaterial()
    {
        if (defaultMaterialIndex) {
            return defaultMaterialIndex - 1;
        }

        aiMaterial* out_mat = new aiMaterial();
        materials.push_back(out_mat);

        const aiColor3D diffuse = aiColor3D(0.8f,0.8f,0.8f);
        out_mat->AddProperty(&diffuse,1,AI_MATKEY_COLOR_DIFFUSE);

        aiString s;
        s.Set(AI_DEFAULT_MATERIAL_NAME);

        out_mat->AddProperty(&s,AI_MATKEY_NAME);

        defaultMaterialIndex = static_cast<unsigned int>(materials.size());
        return defaultMaterialIndex - 1;
    }


    // ------------------------------------------------------------------------------------------------
    // Material -> aiMaterial
    unsigned int ConvertMaterial(const Material& material, const MeshGeometry* const mesh)
    {
        const PropertyTable& props = material.Props();

        // generate empty output material
        aiMaterial* out_mat = new aiMaterial();
        materials_converted[&material] = static_cast<unsigned int>(materials.size());

        materials.push_back(out_mat);

        aiString str;

        // stip Material:: prefix
        std::string name = material.Name();
        if(name.substr(0,10) == "Material::") {
            name = name.substr(10);
        }

        // set material name if not empty - this could happen
        // and there should be no key for it in this case.
        if(name.length()) {
            str.Set(name);
            out_mat->AddProperty(&str,AI_MATKEY_NAME);
        }

        // shading stuff and colors
        SetShadingPropertiesCommon(out_mat,props);

        // texture assignments
        SetTextureProperties(out_mat,material.Textures(), mesh);
        SetTextureProperties(out_mat,material.LayeredTextures(), mesh);

        return static_cast<unsigned int>(materials.size() - 1);
    }


    // ------------------------------------------------------------------------------------------------
    void TrySetTextureProperties(aiMaterial* out_mat, const TextureMap& textures,
        const std::string& propName,
        aiTextureType target, const MeshGeometry* const mesh)
    {
        TextureMap::const_iterator it = textures.find(propName);
        if(it == textures.end()) {
            return;
        }

        const Texture* const tex = (*it).second;
        if(tex !=0 )
        {
            aiString path;
            path.Set(tex->RelativeFilename());

            out_mat->AddProperty(&path,_AI_MATKEY_TEXTURE_BASE,target,0);

            aiUVTransform uvTrafo;
            // XXX handle all kinds of UV transformations
            uvTrafo.mScaling = tex->UVScaling();
            uvTrafo.mTranslation = tex->UVTranslation();
            out_mat->AddProperty(&uvTrafo,1,_AI_MATKEY_UVTRANSFORM_BASE,target,0);

            const PropertyTable& props = tex->Props();

            int uvIndex = 0;

            bool ok;
            const std::string& uvSet = PropertyGet<std::string>(props,"UVSet",ok);
            if(ok) {
                // "default" is the name which usually appears in the FbxFileTexture template
                if(uvSet != "default" && uvSet.length()) {
                    // this is a bit awkward - we need to find a mesh that uses this
                    // material and scan its UV channels for the given UV name because
                    // assimp references UV channels by index, not by name.

                    // XXX: the case that UV channels may appear in different orders
                    // in meshes is unhandled. A possible solution would be to sort
                    // the UV channels alphabetically, but this would have the side
                    // effect that the primary (first) UV channel would sometimes
                    // be moved, causing trouble when users read only the first
                    // UV channel and ignore UV channel assignments altogether.

                    const unsigned int matIndex = static_cast<unsigned int>(std::distance(materials.begin(),
                        std::find(materials.begin(),materials.end(),out_mat)
                    ));


          uvIndex = -1;
          if (!mesh)
          {
                      BOOST_FOREACH(const MeshMap::value_type& v,meshes_converted) {
                          const MeshGeometry* const mesh = dynamic_cast<const MeshGeometry*> (v.first);
                          if(!mesh) {
                              continue;
                          }

                          const MatIndexArray& mats = mesh->GetMaterialIndices();
                          if(std::find(mats.begin(),mats.end(),matIndex) == mats.end()) {
                              continue;
                          }

                          int index = -1;
                          for (unsigned int i = 0; i < AI_MAX_NUMBER_OF_TEXTURECOORDS; ++i) {
                              if(mesh->GetTextureCoords(i).empty()) {
                                  break;
                              }
                              const std::string& name = mesh->GetTextureCoordChannelName(i);
                              if(name == uvSet) {
                                  index = static_cast<int>(i);
                                  break;
                              }
                          }
                          if(index == -1) {
                              FBXImporter::LogWarn("did not find UV channel named " + uvSet + " in a mesh using this material");
                              continue;
                          }

                          if(uvIndex == -1) {
                              uvIndex = index;
                          }
                          else {
                              FBXImporter::LogWarn("the UV channel named " + uvSet +
                                  " appears at different positions in meshes, results will be wrong");
                          }
                      }
          }
          else
          {
                        int index = -1;
                        for (unsigned int i = 0; i < AI_MAX_NUMBER_OF_TEXTURECOORDS; ++i) {
                            if(mesh->GetTextureCoords(i).empty()) {
                                break;
                            }
                            const std::string& name = mesh->GetTextureCoordChannelName(i);
                            if(name == uvSet) {
                                index = static_cast<int>(i);
                                break;
                            }
                        }
                        if(index == -1) {
                            FBXImporter::LogWarn("did not find UV channel named " + uvSet + " in a mesh using this material");
                        }

                        if(uvIndex == -1) {
                            uvIndex = index;
                        }
          }

                    if(uvIndex == -1) {
                        FBXImporter::LogWarn("failed to resolve UV channel " + uvSet + ", using first UV channel");
                        uvIndex = 0;
                    }
                }
            }

            out_mat->AddProperty(&uvIndex,1,_AI_MATKEY_UVWSRC_BASE,target,0);
        }
    }

    // ------------------------------------------------------------------------------------------------
    void TrySetTextureProperties(aiMaterial* out_mat, const LayeredTextureMap& layeredTextures,
        const std::string& propName,
        aiTextureType target, const MeshGeometry* const mesh)
    {
        LayeredTextureMap::const_iterator it = layeredTextures.find(propName);
        if(it == layeredTextures.end()) {
            return;
        }

        const Texture* const tex = (*it).second->getTexture();

        aiString path;
        path.Set(tex->RelativeFilename());

        out_mat->AddProperty(&path,_AI_MATKEY_TEXTURE_BASE,target,0);

        aiUVTransform uvTrafo;
        // XXX handle all kinds of UV transformations
        uvTrafo.mScaling = tex->UVScaling();
        uvTrafo.mTranslation = tex->UVTranslation();
        out_mat->AddProperty(&uvTrafo,1,_AI_MATKEY_UVTRANSFORM_BASE,target,0);

        const PropertyTable& props = tex->Props();

        int uvIndex = 0;

        bool ok;
        const std::string& uvSet = PropertyGet<std::string>(props,"UVSet",ok);
        if(ok) {
            // "default" is the name which usually appears in the FbxFileTexture template
            if(uvSet != "default" && uvSet.length()) {
                // this is a bit awkward - we need to find a mesh that uses this
                // material and scan its UV channels for the given UV name because
                // assimp references UV channels by index, not by name.

                // XXX: the case that UV channels may appear in different orders
                // in meshes is unhandled. A possible solution would be to sort
                // the UV channels alphabetically, but this would have the side
                // effect that the primary (first) UV channel would sometimes
                // be moved, causing trouble when users read only the first
                // UV channel and ignore UV channel assignments altogether.

                const unsigned int matIndex = static_cast<unsigned int>(std::distance(materials.begin(),
                    std::find(materials.begin(),materials.end(),out_mat)
                    ));

              uvIndex = -1;
        if (!mesh)
        {
                    BOOST_FOREACH(const MeshMap::value_type& v,meshes_converted) {
                        const MeshGeometry* const mesh = dynamic_cast<const MeshGeometry*> (v.first);
                        if(!mesh) {
                            continue;
                        }

                        const MatIndexArray& mats = mesh->GetMaterialIndices();
                        if(std::find(mats.begin(),mats.end(),matIndex) == mats.end()) {
                            continue;
                        }

                        int index = -1;
                        for (unsigned int i = 0; i < AI_MAX_NUMBER_OF_TEXTURECOORDS; ++i) {
                            if(mesh->GetTextureCoords(i).empty()) {
                                break;
                            }
                            const std::string& name = mesh->GetTextureCoordChannelName(i);
                            if(name == uvSet) {
                                index = static_cast<int>(i);
                                break;
                            }
                        }
                        if(index == -1) {
                            FBXImporter::LogWarn("did not find UV channel named " + uvSet + " in a mesh using this material");
                            continue;
                        }

                        if(uvIndex == -1) {
                            uvIndex = index;
                        }
                        else {
                            FBXImporter::LogWarn("the UV channel named " + uvSet +
                                " appears at different positions in meshes, results will be wrong");
                        }
                    }
        }
        else
        {
                    int index = -1;
                    for (unsigned int i = 0; i < AI_MAX_NUMBER_OF_TEXTURECOORDS; ++i) {
                        if(mesh->GetTextureCoords(i).empty()) {
                            break;
                        }
                        const std::string& name = mesh->GetTextureCoordChannelName(i);
                        if(name == uvSet) {
                            index = static_cast<int>(i);
                            break;
                        }
                    }
                    if(index == -1) {
                        FBXImporter::LogWarn("did not find UV channel named " + uvSet + " in a mesh using this material");
                    }

                    if(uvIndex == -1) {
                        uvIndex = index;
                    }
        }

                if(uvIndex == -1) {
                    FBXImporter::LogWarn("failed to resolve UV channel " + uvSet + ", using first UV channel");
                    uvIndex = 0;
                }
            }
        }

        out_mat->AddProperty(&uvIndex,1,_AI_MATKEY_UVWSRC_BASE,target,0);
    }

    // ------------------------------------------------------------------------------------------------
    void SetTextureProperties(aiMaterial* out_mat, const TextureMap& textures, const MeshGeometry* const mesh)
    {
        TrySetTextureProperties(out_mat, textures, "DiffuseColor", aiTextureType_DIFFUSE, mesh);
        TrySetTextureProperties(out_mat, textures, "AmbientColor", aiTextureType_AMBIENT, mesh);
        TrySetTextureProperties(out_mat, textures, "EmissiveColor", aiTextureType_EMISSIVE, mesh);
        TrySetTextureProperties(out_mat, textures, "SpecularColor", aiTextureType_SPECULAR, mesh);
        TrySetTextureProperties(out_mat, textures, "TransparentColor", aiTextureType_OPACITY, mesh);
        TrySetTextureProperties(out_mat, textures, "ReflectionColor", aiTextureType_REFLECTION, mesh);
        TrySetTextureProperties(out_mat, textures, "DisplacementColor", aiTextureType_DISPLACEMENT, mesh);
        TrySetTextureProperties(out_mat, textures, "NormalMap", aiTextureType_NORMALS, mesh);
        TrySetTextureProperties(out_mat, textures, "Bump", aiTextureType_HEIGHT, mesh);
        TrySetTextureProperties(out_mat, textures, "ShininessExponent", aiTextureType_SHININESS, mesh);
    }

    // ------------------------------------------------------------------------------------------------
    void SetTextureProperties(aiMaterial* out_mat, const LayeredTextureMap& layeredTextures, const MeshGeometry* const mesh)
    {
        TrySetTextureProperties(out_mat, layeredTextures, "DiffuseColor", aiTextureType_DIFFUSE, mesh);
        TrySetTextureProperties(out_mat, layeredTextures, "AmbientColor", aiTextureType_AMBIENT, mesh);
        TrySetTextureProperties(out_mat, layeredTextures, "EmissiveColor", aiTextureType_EMISSIVE, mesh);
        TrySetTextureProperties(out_mat, layeredTextures, "SpecularColor", aiTextureType_SPECULAR, mesh);
        TrySetTextureProperties(out_mat, layeredTextures, "TransparentColor", aiTextureType_OPACITY, mesh);
        TrySetTextureProperties(out_mat, layeredTextures, "ReflectionColor", aiTextureType_REFLECTION, mesh);
        TrySetTextureProperties(out_mat, layeredTextures, "DisplacementColor", aiTextureType_DISPLACEMENT, mesh);
        TrySetTextureProperties(out_mat, layeredTextures, "NormalMap", aiTextureType_NORMALS, mesh);
        TrySetTextureProperties(out_mat, layeredTextures, "Bump", aiTextureType_HEIGHT, mesh);
        TrySetTextureProperties(out_mat, layeredTextures, "ShininessExponent", aiTextureType_SHININESS, mesh);
    }


    // ------------------------------------------------------------------------------------------------
    aiColor3D GetColorPropertyFromMaterial(const PropertyTable& props, const std::string& baseName,
        bool& result)
    {
        result = true;

        bool ok;
        const aiVector3D& Diffuse = PropertyGet<aiVector3D>(props,baseName,ok);
        if(ok) {
            return aiColor3D(Diffuse.x,Diffuse.y,Diffuse.z);
        }
        else {
            aiVector3D DiffuseColor = PropertyGet<aiVector3D>(props,baseName + "Color",ok);
            if(ok) {
                float DiffuseFactor = PropertyGet<float>(props,baseName + "Factor",ok);
                if(ok) {
                    DiffuseColor *= DiffuseFactor;
                }

                return aiColor3D(DiffuseColor.x,DiffuseColor.y,DiffuseColor.z);
            }
        }
        result = false;
        return aiColor3D(0.0f,0.0f,0.0f);
    }


    // ------------------------------------------------------------------------------------------------
    void SetShadingPropertiesCommon(aiMaterial* out_mat, const PropertyTable& props)
    {
        // set shading properties. There are various, redundant ways in which FBX materials
        // specify their shading settings (depending on shading models, prop
        // template etc.). No idea which one is right in a particular context.
        // Just try to make sense of it - there's no spec to verify this against,
        // so why should we.
        bool ok;
        const aiColor3D& Diffuse = GetColorPropertyFromMaterial(props,"Diffuse",ok);
        if(ok) {
            out_mat->AddProperty(&Diffuse,1,AI_MATKEY_COLOR_DIFFUSE);
        }

        const aiColor3D& Emissive = GetColorPropertyFromMaterial(props,"Emissive",ok);
        if(ok) {
            out_mat->AddProperty(&Emissive,1,AI_MATKEY_COLOR_EMISSIVE);
        }

        const aiColor3D& Ambient = GetColorPropertyFromMaterial(props,"Ambient",ok);
        if(ok) {
            out_mat->AddProperty(&Ambient,1,AI_MATKEY_COLOR_AMBIENT);
        }

        const aiColor3D& Specular = GetColorPropertyFromMaterial(props,"Specular",ok);
        if(ok) {
            out_mat->AddProperty(&Specular,1,AI_MATKEY_COLOR_SPECULAR);
        }

        const float Opacity = PropertyGet<float>(props,"Opacity",ok);
        if(ok) {
            out_mat->AddProperty(&Opacity,1,AI_MATKEY_OPACITY);
        }

        const float Reflectivity = PropertyGet<float>(props,"Reflectivity",ok);
        if(ok) {
            out_mat->AddProperty(&Reflectivity,1,AI_MATKEY_REFLECTIVITY);
        }

        const float Shininess = PropertyGet<float>(props,"Shininess",ok);
        if(ok) {
            out_mat->AddProperty(&Shininess,1,AI_MATKEY_SHININESS_STRENGTH);
        }

        const float ShininessExponent = PropertyGet<float>(props,"ShininessExponent",ok);
        if(ok) {
            out_mat->AddProperty(&ShininessExponent,1,AI_MATKEY_SHININESS);
        }
    }


    // ------------------------------------------------------------------------------------------------
    // get the number of fps for a FrameRate enumerated value
    static double FrameRateToDouble(FileGlobalSettings::FrameRate fp, double customFPSVal = -1.0)
    {
        switch(fp) {
            case FileGlobalSettings::FrameRate_DEFAULT:
                return 1.0;

            case FileGlobalSettings::FrameRate_120:
                return 120.0;

            case FileGlobalSettings::FrameRate_100:
                return 100.0;

            case FileGlobalSettings::FrameRate_60:
                return 60.0;

            case FileGlobalSettings::FrameRate_50:
                return 50.0;

            case FileGlobalSettings::FrameRate_48:
                return 48.0;

            case FileGlobalSettings::FrameRate_30:
            case FileGlobalSettings::FrameRate_30_DROP:
                return 30.0;

            case FileGlobalSettings::FrameRate_NTSC_DROP_FRAME:
            case FileGlobalSettings::FrameRate_NTSC_FULL_FRAME:
                return 29.9700262;

            case FileGlobalSettings::FrameRate_PAL:
                return 25.0;

            case FileGlobalSettings::FrameRate_CINEMA:
                return 24.0;

            case FileGlobalSettings::FrameRate_1000:
                return 1000.0;

            case FileGlobalSettings::FrameRate_CINEMA_ND:
                return 23.976;

            case FileGlobalSettings::FrameRate_CUSTOM:
                return customFPSVal;

            case FileGlobalSettings::FrameRate_MAX: // this is to silence compiler warnings
                break;
        }

        ai_assert(false);
        return -1.0f;
    }


    // ------------------------------------------------------------------------------------------------
    // convert animation data to aiAnimation et al
    void ConvertAnimations()
    {
        // first of all determine framerate
        const FileGlobalSettings::FrameRate fps = doc.GlobalSettings().TimeMode();
        const float custom = doc.GlobalSettings().CustomFrameRate();
        anim_fps = FrameRateToDouble(fps, custom);

        const std::vector<const AnimationStack*>& animations = doc.AnimationStacks();
        BOOST_FOREACH(const AnimationStack* stack, animations) {
            ConvertAnimationStack(*stack);
        }
    }


    // ------------------------------------------------------------------------------------------------
    // rename a node already partially converted. fixed_name is a string previously returned by
    // FixNodeName, new_name specifies the string FixNodeName should return on all further invocations
    // which would previously have returned the old value.
    //
    // this also updates names in node animations, cameras and light sources and is thus slow.
    //
    // NOTE: the caller is responsible for ensuring that the new name is unique and does
    // not collide with any other identifiers. The best way to ensure this is to only
    // append to the old name, which is guaranteed to match these requirements.
    void RenameNode(const std::string& fixed_name, const std::string& new_name)
    {
        ai_assert(node_names.find(fixed_name) != node_names.end());
        ai_assert(node_names.find(new_name) == node_names.end());

        renamed_nodes[fixed_name] = new_name;

        const aiString fn(fixed_name);

        BOOST_FOREACH(aiCamera* cam, cameras) {
            if (cam->mName == fn) {
                cam->mName.Set(new_name);
                break;
            }
        }

        BOOST_FOREACH(aiLight* light, lights) {
            if (light->mName == fn) {
                light->mName.Set(new_name);
                break;
            }
        }

        BOOST_FOREACH(aiAnimation* anim, animations) {
            for (unsigned int i = 0; i < anim->mNumChannels; ++i) {
                aiNodeAnim* const na = anim->mChannels[i];
                if (na->mNodeName == fn) {
                    na->mNodeName.Set(new_name);
                    break;
                }
            }
        }
    }


    // ------------------------------------------------------------------------------------------------
    // takes a fbx node name and returns the identifier to be used in the assimp output scene.
    // the function is guaranteed to provide consistent results over multiple invocations
    // UNLESS RenameNode() is called for a particular node name.
    std::string FixNodeName(const std::string& name)
    {
        // strip Model:: prefix, avoiding ambiguities (i.e. don't strip if
        // this causes ambiguities, well possible between empty identifiers,
        // such as "Model::" and ""). Make sure the behaviour is consistent
        // across multiple calls to FixNodeName().
        if(name.substr(0,7) == "Model::") {
            std::string temp = name.substr(7);

            const NodeNameMap::const_iterator it = node_names.find(temp);
            if (it != node_names.end()) {
                if (!(*it).second) {
                    return FixNodeName(name + "_");
                }
            }
            node_names[temp] = true;

            const NameNameMap::const_iterator rit = renamed_nodes.find(temp);
            return rit == renamed_nodes.end() ? temp : (*rit).second;
        }

        const NodeNameMap::const_iterator it = node_names.find(name);
        if (it != node_names.end()) {
            if ((*it).second) {
                return FixNodeName(name + "_");
            }
        }
        node_names[name] = false;

        const NameNameMap::const_iterator rit = renamed_nodes.find(name);
        return rit == renamed_nodes.end() ? name : (*rit).second;
    }


    typedef std::map<const AnimationCurveNode*, const AnimationLayer*> LayerMap;

    // XXX: better use multi_map ..
    typedef std::map<std::string, std::vector<const AnimationCurveNode*> > NodeMap;


    // ------------------------------------------------------------------------------------------------
    void ConvertAnimationStack(const AnimationStack& st)
    {
        const AnimationLayerList& layers = st.Layers();
        if(layers.empty()) {
            return;
        }

        aiAnimation* const anim = new aiAnimation();
        animations.push_back(anim);

        // strip AnimationStack:: prefix
        std::string name = st.Name();
        if (name.substr(0, 16) == "AnimationStack::") {
            name = name.substr(16);
        }
        else if (name.substr(0, 11) == "AnimStack::") {
            name = name.substr(11);
        }

        anim->mName.Set(name);

        // need to find all nodes for which we need to generate node animations -
        // it may happen that we need to merge multiple layers, though.
        NodeMap node_map;

        // reverse mapping from curves to layers, much faster than querying
        // the FBX DOM for it.
        LayerMap layer_map;

        const char* prop_whitelist[] = {
            "Lcl Scaling",
            "Lcl Rotation",
            "Lcl Translation"
        };

        BOOST_FOREACH(const AnimationLayer* layer, layers) {
            ai_assert(layer);

            const AnimationCurveNodeList& nodes = layer->Nodes(prop_whitelist, 3);
            BOOST_FOREACH(const AnimationCurveNode* node, nodes) {
                ai_assert(node);

                const Model* const model = dynamic_cast<const Model*>(node->Target());
                // this can happen - it could also be a NodeAttribute (i.e. for camera animations)
                if(!model) {
                    continue;
                }

                const std::string& name = FixNodeName(model->Name());
                node_map[name].push_back(node);

                layer_map[node] = layer;
            }
        }

        // generate node animations
        std::vector<aiNodeAnim*> node_anims;

        double min_time = 1e10;
        double max_time = -1e10;

        int64_t start_time = st.LocalStart();
        int64_t stop_time = st.LocalStop();
        double start_timeF = CONVERT_FBX_TIME(start_time);
        double stop_timeF = CONVERT_FBX_TIME(stop_time);

        try {
            BOOST_FOREACH(const NodeMap::value_type& kv, node_map) {
                GenerateNodeAnimations(node_anims,
                    kv.first,
                    kv.second,
                    layer_map,
                    start_time, stop_time,
                    max_time,
                    min_time);
            }
        }
        catch(std::exception&) {
            std::for_each(node_anims.begin(), node_anims.end(), Util::delete_fun<aiNodeAnim>());
            throw;
        }

        if(node_anims.size()) {
            anim->mChannels = new aiNodeAnim*[node_anims.size()]();
            anim->mNumChannels = static_cast<unsigned int>(node_anims.size());

            std::swap_ranges(node_anims.begin(),node_anims.end(),anim->mChannels);
        }
        else {
            // empty animations would fail validation, so drop them
            delete anim;
            animations.pop_back();
            FBXImporter::LogInfo("ignoring empty AnimationStack (using IK?): " + name);
            return;
        }

        //adjust relative timing for animation
        {
            double start_fps = start_timeF * anim_fps;

            for (unsigned int c = 0; c < anim->mNumChannels; c++)
            {
                aiNodeAnim* channel = anim->mChannels[c];
                for (uint32_t i = 0; i < channel->mNumPositionKeys; i++)
                    channel->mPositionKeys[i].mTime -= start_fps;
                for (uint32_t i = 0; i < channel->mNumRotationKeys; i++)
                    channel->mRotationKeys[i].mTime -= start_fps;
                for (uint32_t i = 0; i < channel->mNumScalingKeys; i++)
                    channel->mScalingKeys[i].mTime -= start_fps;
            }

            max_time -= min_time;
        }

        // for some mysterious reason, mDuration is simply the maximum key -- the
        // validator always assumes animations to start at zero.
        anim->mDuration = (stop_timeF - start_timeF) * anim_fps;
        anim->mTicksPerSecond = anim_fps;
    }


    // ------------------------------------------------------------------------------------------------
    void GenerateNodeAnimations(std::vector<aiNodeAnim*>& node_anims,
        const std::string& fixed_name,
        const std::vector<const AnimationCurveNode*>& curves,
        const LayerMap& layer_map,
        int64_t start, int64_t stop,
        double& max_time,
        double& min_time)
    {

        NodeMap node_property_map;
        ai_assert(curves.size());

        // sanity check whether the input is ok
#ifdef ASSIMP_BUILD_DEBUG
        { const Object* target = NULL;
        BOOST_FOREACH(const AnimationCurveNode* node, curves) {
            if(!target) {
                target = node->Target();
            }
            ai_assert(node->Target() == target);
        }}
#endif

        const AnimationCurveNode* curve_node = NULL;
        BOOST_FOREACH(const AnimationCurveNode* node, curves) {
            ai_assert(node);

            if (node->TargetProperty().empty()) {
                FBXImporter::LogWarn("target property for animation curve not set: " + node->Name());
                continue;
            }

            curve_node = node;
            if (node->Curves().empty()) {
                FBXImporter::LogWarn("no animation curves assigned to AnimationCurveNode: " + node->Name());
                continue;
            }

            node_property_map[node->TargetProperty()].push_back(node);
        }

        ai_assert(curve_node);
        ai_assert(curve_node->TargetAsModel());

        const Model& target = *curve_node->TargetAsModel();

        // check for all possible transformation components
        NodeMap::const_iterator chain[TransformationComp_MAXIMUM];

        bool has_any = false;
        bool has_complex = false;

        for (size_t i = 0; i < TransformationComp_MAXIMUM; ++i) {
            const TransformationComp comp = static_cast<TransformationComp>(i);

            // inverse pivots don't exist in the input, we just generate them
            if (comp == TransformationComp_RotationPivotInverse || comp == TransformationComp_ScalingPivotInverse) {
                chain[i] = node_property_map.end();
                continue;
            }

            chain[i] = node_property_map.find(NameTransformationCompProperty(comp));
            if (chain[i] != node_property_map.end()) {

                // check if this curves contains redundant information by looking
                // up the corresponding node's transformation chain.
                if (doc.Settings().optimizeEmptyAnimationCurves &&
                    IsRedundantAnimationData(target, comp, (*chain[i]).second)) {

                    FBXImporter::LogDebug("dropping redundant animation channel for node " + target.Name());
                    continue;
                }

                has_any = true;

                if (comp != TransformationComp_Rotation && comp != TransformationComp_Scaling && comp != TransformationComp_Translation &&
                    comp != TransformationComp_GeometricScaling && comp != TransformationComp_GeometricRotation && comp != TransformationComp_GeometricTranslation )
                {
                    has_complex = true;
                }
            }
        }

        if (!has_any) {
            FBXImporter::LogWarn("ignoring node animation, did not find any transformation key frames");
            return;
        }

        // this needs to play nicely with GenerateTransformationNodeChain() which will
        // be invoked _later_ (animations come first). If this node has only rotation,
        // scaling and translation _and_ there are no animated other components either,
        // we can use a single node and also a single node animation channel.
        if (!has_complex && !NeedsComplexTransformationChain(target)) {

            aiNodeAnim* const nd = GenerateSimpleNodeAnim(fixed_name, target, chain,
                node_property_map.end(),
                layer_map,
                start, stop,
                max_time,
                min_time,
                true // input is TRS order, assimp is SRT
                );

            ai_assert(nd);
            if (nd->mNumPositionKeys == 0 && nd->mNumRotationKeys == 0 && nd->mNumScalingKeys == 0) {
                delete nd;
            }
            else {
                node_anims.push_back(nd);
            }
            return;
        }

        // otherwise, things get gruesome and we need separate animation channels
        // for each part of the transformation chain. Remember which channels
        // we generated and pass this information to the node conversion
        // code to avoid nodes that have identity transform, but non-identity
        // animations, being dropped.
        unsigned int flags = 0, bit = 0x1;
        for (size_t i = 0; i < TransformationComp_MAXIMUM; ++i, bit <<= 1) {
            const TransformationComp comp = static_cast<TransformationComp>(i);

            if (chain[i] != node_property_map.end()) {
                flags |= bit;

                ai_assert(comp != TransformationComp_RotationPivotInverse);
                ai_assert(comp != TransformationComp_ScalingPivotInverse);

                const std::string& chain_name = NameTransformationChainNode(fixed_name, comp);

                aiNodeAnim* na;
                switch(comp)
                {
                case TransformationComp_Rotation:
                case TransformationComp_PreRotation:
                case TransformationComp_PostRotation:
                case TransformationComp_GeometricRotation:
                    na = GenerateRotationNodeAnim(chain_name,
                        target,
                        (*chain[i]).second,
                        layer_map,
                        start, stop,
                        max_time,
                        min_time);

                    break;

                case TransformationComp_RotationOffset:
                case TransformationComp_RotationPivot:
                case TransformationComp_ScalingOffset:
                case TransformationComp_ScalingPivot:
                case TransformationComp_Translation:
                case TransformationComp_GeometricTranslation:
                    na = GenerateTranslationNodeAnim(chain_name,
                        target,
                        (*chain[i]).second,
                        layer_map,
                        start, stop,
                        max_time,
                        min_time);

                    // pivoting requires us to generate an implicit inverse channel to undo the pivot translation
                    if (comp == TransformationComp_RotationPivot) {
                        const std::string& invName = NameTransformationChainNode(fixed_name,
                            TransformationComp_RotationPivotInverse);

                        aiNodeAnim* const inv = GenerateTranslationNodeAnim(invName,
                            target,
                            (*chain[i]).second,
                            layer_map,
                            start, stop,
                            max_time,
                            min_time,
                            true);

                        ai_assert(inv);
                        if (inv->mNumPositionKeys == 0 && inv->mNumRotationKeys == 0 && inv->mNumScalingKeys == 0) {
                            delete inv;
                        }
                        else {
                            node_anims.push_back(inv);
                        }

                        ai_assert(TransformationComp_RotationPivotInverse > i);
                        flags |= bit << (TransformationComp_RotationPivotInverse - i);
                    }
                    else if (comp == TransformationComp_ScalingPivot) {
                        const std::string& invName = NameTransformationChainNode(fixed_name,
                            TransformationComp_ScalingPivotInverse);

                        aiNodeAnim* const inv = GenerateTranslationNodeAnim(invName,
                            target,
                            (*chain[i]).second,
                            layer_map,
                            start, stop,
                            max_time,
                            min_time,
                            true);

                        ai_assert(inv);
                        if (inv->mNumPositionKeys == 0 && inv->mNumRotationKeys == 0 && inv->mNumScalingKeys == 0) {
                            delete inv;
                        }
                        else {
                            node_anims.push_back(inv);
                        }

                        ai_assert(TransformationComp_RotationPivotInverse > i);
                        flags |= bit << (TransformationComp_RotationPivotInverse - i);
                    }

                    break;

                case TransformationComp_Scaling:
                case TransformationComp_GeometricScaling:
                    na = GenerateScalingNodeAnim(chain_name,
                        target,
                        (*chain[i]).second,
                        layer_map,
                        start, stop,
                        max_time,
                        min_time);

                    break;

                default:
                    ai_assert(false);
                }

                ai_assert(na);
                if (na->mNumPositionKeys == 0 && na->mNumRotationKeys == 0 && na->mNumScalingKeys == 0) {
                    delete na;
                }
                else {
                    node_anims.push_back(na);
                }
                continue;
            }
        }

        node_anim_chain_bits[fixed_name] = flags;
    }


    // ------------------------------------------------------------------------------------------------
    bool IsRedundantAnimationData(const Model& target,
        TransformationComp comp,
        const std::vector<const AnimationCurveNode*>& curves)
    {
        ai_assert(curves.size());

        // look for animation nodes with
        //  * sub channels for all relevant components set
        //  * one key/value pair per component
        //  * combined values match up the corresponding value in the bind pose node transformation
        // only such nodes are 'redundant' for this function.

        if (curves.size() > 1) {
            return false;
        }

        const AnimationCurveNode& nd = *curves.front();
        const AnimationCurveMap& sub_curves = nd.Curves();

        const AnimationCurveMap::const_iterator dx = sub_curves.find("d|X");
        const AnimationCurveMap::const_iterator dy = sub_curves.find("d|Y");
        const AnimationCurveMap::const_iterator dz = sub_curves.find("d|Z");

        if (dx == sub_curves.end() || dy == sub_curves.end() || dz == sub_curves.end()) {
            return false;
        }

        const KeyValueList& vx = (*dx).second->GetValues();
        const KeyValueList& vy = (*dy).second->GetValues();
        const KeyValueList& vz = (*dz).second->GetValues();

        if(vx.size() != 1 || vy.size() != 1 || vz.size() != 1) {
            return false;
        }

        const aiVector3D dyn_val = aiVector3D(vx[0], vy[0], vz[0]);
        const aiVector3D& static_val = PropertyGet<aiVector3D>(target.Props(),
            NameTransformationCompProperty(comp),
            TransformationCompDefaultValue(comp)
        );

        const float epsilon = 1e-6f;
        return (dyn_val - static_val).SquareLength() < epsilon;
    }


    // ------------------------------------------------------------------------------------------------
    aiNodeAnim* GenerateRotationNodeAnim(const std::string& name,
        const Model& target,
        const std::vector<const AnimationCurveNode*>& curves,
        const LayerMap& layer_map,
        int64_t start, int64_t stop,
        double& max_time,
        double& min_time)
    {
        ScopeGuard<aiNodeAnim> na(new aiNodeAnim());
        na->mNodeName.Set(name);

        ConvertRotationKeys(na, curves, layer_map, start, stop, max_time, min_time, target.RotationOrder());

        // dummy scaling key
        na->mScalingKeys = new aiVectorKey[1];
        na->mNumScalingKeys = 1;

        na->mScalingKeys[0].mTime = 0.;
        na->mScalingKeys[0].mValue = aiVector3D(1.0f,1.0f,1.0f);

        // dummy position key
        na->mPositionKeys = new aiVectorKey[1];
        na->mNumPositionKeys = 1;

        na->mPositionKeys[0].mTime = 0.;
        na->mPositionKeys[0].mValue = aiVector3D();

        return na.dismiss();
    }


    // ------------------------------------------------------------------------------------------------
    aiNodeAnim* GenerateScalingNodeAnim(const std::string& name,
        const Model& /*target*/,
        const std::vector<const AnimationCurveNode*>& curves,
        const LayerMap& layer_map,
        int64_t start, int64_t stop,
        double& max_time,
        double& min_time)
    {
        ScopeGuard<aiNodeAnim> na(new aiNodeAnim());
        na->mNodeName.Set(name);

        ConvertScaleKeys(na, curves, layer_map, start, stop, max_time, min_time);

        // dummy rotation key
        na->mRotationKeys = new aiQuatKey[1];
        na->mNumRotationKeys = 1;

        na->mRotationKeys[0].mTime = 0.;
        na->mRotationKeys[0].mValue = aiQuaternion();

        // dummy position key
        na->mPositionKeys = new aiVectorKey[1];
        na->mNumPositionKeys = 1;

        na->mPositionKeys[0].mTime = 0.;
        na->mPositionKeys[0].mValue = aiVector3D();

        return na.dismiss();
    }


    // ------------------------------------------------------------------------------------------------
    aiNodeAnim* GenerateTranslationNodeAnim(const std::string& name,
        const Model& /*target*/,
        const std::vector<const AnimationCurveNode*>& curves,
        const LayerMap& layer_map,
        int64_t start, int64_t stop,
        double& max_time,
        double& min_time,
        bool inverse = false)
    {
        ScopeGuard<aiNodeAnim> na(new aiNodeAnim());
        na->mNodeName.Set(name);

        ConvertTranslationKeys(na, curves, layer_map, start, stop, max_time, min_time);

        if (inverse) {
            for (unsigned int i = 0; i < na->mNumPositionKeys; ++i) {
                na->mPositionKeys[i].mValue *= -1.0f;
            }
        }

        // dummy scaling key
        na->mScalingKeys = new aiVectorKey[1];
        na->mNumScalingKeys = 1;

        na->mScalingKeys[0].mTime = 0.;
        na->mScalingKeys[0].mValue = aiVector3D(1.0f,1.0f,1.0f);

        // dummy rotation key
        na->mRotationKeys = new aiQuatKey[1];
        na->mNumRotationKeys = 1;

        na->mRotationKeys[0].mTime = 0.;
        na->mRotationKeys[0].mValue = aiQuaternion();

        return na.dismiss();
    }


    // ------------------------------------------------------------------------------------------------
    // generate node anim, extracting only Rotation, Scaling and Translation from the given chain
    aiNodeAnim* GenerateSimpleNodeAnim(const std::string& name,
        const Model& target,
        NodeMap::const_iterator chain[TransformationComp_MAXIMUM],
        NodeMap::const_iterator iter_end,
        const LayerMap& layer_map,
        int64_t start, int64_t stop,
        double& max_time,
        double& min_time,
        bool reverse_order = false)

    {
        ScopeGuard<aiNodeAnim> na(new aiNodeAnim());
        na->mNodeName.Set(name);

        const PropertyTable& props = target.Props();

        // need to convert from TRS order to SRT?
        if(reverse_order) {

            aiVector3D def_scale, def_translate;
            aiQuaternion def_rot;

            KeyFrameListList scaling;
            KeyFrameListList translation;
            KeyFrameListList rotation;

            if(chain[TransformationComp_Scaling] != iter_end) {
                scaling = GetKeyframeList((*chain[TransformationComp_Scaling]).second, start, stop);
            }
            else {
                def_scale = PropertyGet(props,"Lcl Scaling",aiVector3D(1.f,1.f,1.f));
            }

            if(chain[TransformationComp_Translation] != iter_end) {
                translation = GetKeyframeList((*chain[TransformationComp_Translation]).second, start, stop);
            }
            else {
                def_translate = PropertyGet(props,"Lcl Translation",aiVector3D(0.f,0.f,0.f));
            }

            if(chain[TransformationComp_Rotation] != iter_end) {
                rotation = GetKeyframeList((*chain[TransformationComp_Rotation]).second, start, stop);
            }
            else {
                def_rot = EulerToQuaternion(PropertyGet(props,"Lcl Rotation",aiVector3D(0.f,0.f,0.f)),
                    target.RotationOrder());
            }

            KeyFrameListList joined;
            joined.insert(joined.end(), scaling.begin(), scaling.end());
            joined.insert(joined.end(), translation.begin(), translation.end());
            joined.insert(joined.end(), rotation.begin(), rotation.end());

            const KeyTimeList& times = GetKeyTimeList(joined);

            aiQuatKey* out_quat = new aiQuatKey[times.size()];
            aiVectorKey* out_scale = new aiVectorKey[times.size()];
            aiVectorKey* out_translation = new aiVectorKey[times.size()];

            if (times.size())
            {
                ConvertTransformOrder_TRStoSRT(out_quat, out_scale, out_translation,
                    scaling,
                    translation,
                    rotation,
                    times,
                    max_time,
                    min_time,
                    target.RotationOrder(),
                    def_scale,
                    def_translate,
                    def_rot);
            }

            // XXX remove duplicates / redundant keys which this operation did
            // likely produce if not all three channels were equally dense.

            na->mNumScalingKeys = static_cast<unsigned int>(times.size());
            na->mNumRotationKeys = na->mNumScalingKeys;
            na->mNumPositionKeys = na->mNumScalingKeys;

            na->mScalingKeys = out_scale;
            na->mRotationKeys = out_quat;
            na->mPositionKeys = out_translation;
        }
        else {

            // if a particular transformation is not given, grab it from
            // the corresponding node to meet the semantics of aiNodeAnim,
            // which requires all of rotation, scaling and translation
            // to be set.
            if(chain[TransformationComp_Scaling] != iter_end) {
                ConvertScaleKeys(na, (*chain[TransformationComp_Scaling]).second,
                    layer_map,
                    start, stop,
                    max_time,
                    min_time);
            }
            else {
                na->mScalingKeys = new aiVectorKey[1];
                na->mNumScalingKeys = 1;

                na->mScalingKeys[0].mTime = 0.;
                na->mScalingKeys[0].mValue = PropertyGet(props,"Lcl Scaling",
                    aiVector3D(1.f,1.f,1.f));
            }

            if(chain[TransformationComp_Rotation] != iter_end) {
                ConvertRotationKeys(na, (*chain[TransformationComp_Rotation]).second,
                    layer_map,
                    start, stop,
                    max_time,
                    min_time,
                    target.RotationOrder());
            }
            else {
                na->mRotationKeys = new aiQuatKey[1];
                na->mNumRotationKeys = 1;

                na->mRotationKeys[0].mTime = 0.;
                na->mRotationKeys[0].mValue = EulerToQuaternion(
                    PropertyGet(props,"Lcl Rotation",aiVector3D(0.f,0.f,0.f)),
                    target.RotationOrder());
            }

            if(chain[TransformationComp_Translation] != iter_end) {
                ConvertTranslationKeys(na, (*chain[TransformationComp_Translation]).second,
                    layer_map,
                    start, stop,
                    max_time,
                    min_time);
            }
            else {
                na->mPositionKeys = new aiVectorKey[1];
                na->mNumPositionKeys = 1;

                na->mPositionKeys[0].mTime = 0.;
                na->mPositionKeys[0].mValue = PropertyGet(props,"Lcl Translation",
                    aiVector3D(0.f,0.f,0.f));
            }

        }
        return na.dismiss();
    }



    // key (time), value, mapto (component index)
    typedef boost::tuple<boost::shared_ptr<KeyTimeList>, boost::shared_ptr<KeyValueList>, unsigned int > KeyFrameList;
    typedef std::vector<KeyFrameList> KeyFrameListList;



    // ------------------------------------------------------------------------------------------------
    KeyFrameListList GetKeyframeList(const std::vector<const AnimationCurveNode*>& nodes, int64_t start, int64_t stop)
    {
        KeyFrameListList inputs;
        inputs.reserve(nodes.size()*3);

        //give some breathing room for rounding errors
        int64_t adj_start = start - 10000;
        int64_t adj_stop = stop + 10000;

        BOOST_FOREACH(const AnimationCurveNode* node, nodes) {
            ai_assert(node);

            const AnimationCurveMap& curves = node->Curves();
            BOOST_FOREACH(const AnimationCurveMap::value_type& kv, curves) {

                unsigned int mapto;
                if (kv.first == "d|X") {
                    mapto = 0;
                }
                else if (kv.first == "d|Y") {
                    mapto = 1;
                }
                else if (kv.first == "d|Z") {
                    mapto = 2;
                }
                else {
                    FBXImporter::LogWarn("ignoring scale animation curve, did not recognize target component");
                    continue;
                }

                const AnimationCurve* const curve = kv.second;
                ai_assert(curve->GetKeys().size() == curve->GetValues().size() && curve->GetKeys().size());

                //get values within the start/stop time window
                boost::shared_ptr<KeyTimeList> Keys(new KeyTimeList());
                boost::shared_ptr<KeyValueList> Values(new KeyValueList());
                const int count = curve->GetKeys().size();
                Keys->reserve(count);
                Values->reserve(count);
                for (int n = 0; n < count; n++)
                {
                    int64_t k = curve->GetKeys().at(n);
                    if (k >= adj_start && k <= adj_stop)
                    {
                        Keys->push_back(k);
                        Values->push_back(curve->GetValues().at(n));
                    }
                }

                inputs.push_back(boost::make_tuple(Keys, Values, mapto));
            }
        }
        return inputs; // pray for NRVO :-)
    }


    // ------------------------------------------------------------------------------------------------
    KeyTimeList GetKeyTimeList(const KeyFrameListList& inputs)
    {
        ai_assert(inputs.size());

        // reserve some space upfront - it is likely that the keyframe lists
        // have matching time values, so max(of all keyframe lists) should
        // be a good estimate.
        KeyTimeList keys;

        size_t estimate = 0;
        BOOST_FOREACH(const KeyFrameList& kfl, inputs) {
            estimate = std::max(estimate, kfl.get<0>()->size());
        }

        keys.reserve(estimate);

        std::vector<unsigned int> next_pos;
        next_pos.resize(inputs.size(),0);

        const size_t count = inputs.size();
        while(true) {

            int64_t min_tick = std::numeric_limits<int64_t>::max();
            for (size_t i = 0; i < count; ++i) {
                const KeyFrameList& kfl = inputs[i];

                if (kfl.get<0>()->size() > next_pos[i] && kfl.get<0>()->at(next_pos[i]) < min_tick) {
                    min_tick = kfl.get<0>()->at(next_pos[i]);
                }
            }

            if (min_tick == std::numeric_limits<int64_t>::max()) {
                break;
            }
            keys.push_back(min_tick);

            for (size_t i = 0; i < count; ++i) {
                const KeyFrameList& kfl = inputs[i];


                while(kfl.get<0>()->size() > next_pos[i] && kfl.get<0>()->at(next_pos[i]) == min_tick) {
                    ++next_pos[i];
                }
            }
        }

        return keys;
    }


    // ------------------------------------------------------------------------------------------------
    void InterpolateKeys(aiVectorKey* valOut,const KeyTimeList& keys, const KeyFrameListList& inputs,
        const bool geom,
        double& max_time,
        double& min_time)

    {
        ai_assert(keys.size());
        ai_assert(valOut);

        std::vector<unsigned int> next_pos;
        const size_t count = inputs.size();

        next_pos.resize(inputs.size(),0);

        BOOST_FOREACH(KeyTimeList::value_type time, keys) {
            float result[3] = {0.0f, 0.0f, 0.0f};
            if(geom) {
                result[0] = result[1] = result[2] = 1.0f;
            }

            for (size_t i = 0; i < count; ++i) {
                const KeyFrameList& kfl = inputs[i];

                const size_t ksize = kfl.get<0>()->size();
                if (ksize > next_pos[i] && kfl.get<0>()->at(next_pos[i]) == time) {
                    ++next_pos[i];
                }

                const size_t id0 = next_pos[i]>0 ? next_pos[i]-1 : 0;
                const size_t id1 = next_pos[i]==ksize ? ksize-1 : next_pos[i];

                // use lerp for interpolation
                const KeyValueList::value_type valueA = kfl.get<1>()->at(id0);
                const KeyValueList::value_type valueB = kfl.get<1>()->at(id1);

                const KeyTimeList::value_type timeA = kfl.get<0>()->at(id0);
                const KeyTimeList::value_type timeB = kfl.get<0>()->at(id1);

                // do the actual interpolation in double-precision arithmetics
                // because it is a bit sensitive to rounding errors.
                const double factor = timeB == timeA ? 0. : static_cast<double>((time - timeA) / (timeB - timeA));
                const float interpValue = static_cast<float>(valueA + (valueB - valueA) * factor);

                if(geom) {
                    result[kfl.get<2>()] *= interpValue;
                }
                else {
                    result[kfl.get<2>()] += interpValue;
                }
            }

            // magic value to convert fbx times to seconds
            valOut->mTime = CONVERT_FBX_TIME(time) * anim_fps;

            min_time = std::min(min_time, valOut->mTime);
            max_time = std::max(max_time, valOut->mTime);

            valOut->mValue.x = result[0];
            valOut->mValue.y = result[1];
            valOut->mValue.z = result[2];

            ++valOut;
        }
    }


    // ------------------------------------------------------------------------------------------------
    void InterpolateKeys(aiQuatKey* valOut,const KeyTimeList& keys, const KeyFrameListList& inputs,
        const bool geom,
        double& maxTime,
        double& minTime,
        Model::RotOrder order)
    {
        ai_assert(keys.size());
        ai_assert(valOut);

        boost::scoped_array<aiVectorKey> temp(new aiVectorKey[keys.size()]);
        InterpolateKeys(temp.get(),keys,inputs,geom,maxTime, minTime);

        aiMatrix4x4 m;

        aiQuaternion lastq;

        for (size_t i = 0, c = keys.size(); i < c; ++i) {

            valOut[i].mTime = temp[i].mTime;


            GetRotationMatrix(order, temp[i].mValue, m);
            aiQuaternion quat = aiQuaternion(aiMatrix3x3(m));

            // take shortest path by checking the inner product
            // http://www.3dkingdoms.com/weekly/weekly.php?a=36
            if (quat.x * lastq.x + quat.y * lastq.y + quat.z * lastq.z + quat.w * lastq.w < 0)
            {
                quat.x = -quat.x;
                quat.y = -quat.y;
                quat.z = -quat.z;
                quat.w = -quat.w;
            }
            lastq = quat;

            valOut[i].mValue = quat;
        }
    }


    // ------------------------------------------------------------------------------------------------
    void ConvertTransformOrder_TRStoSRT(aiQuatKey* out_quat, aiVectorKey* out_scale,
        aiVectorKey* out_translation,
        const KeyFrameListList& scaling,
        const KeyFrameListList& translation,
        const KeyFrameListList& rotation,
        const KeyTimeList& times,
        double& maxTime,
        double& minTime,
        Model::RotOrder order,
        const aiVector3D& def_scale,
        const aiVector3D& def_translate,
        const aiQuaternion& def_rotation)
    {
        if (rotation.size()) {
            InterpolateKeys(out_quat, times, rotation, false, maxTime, minTime, order);
        }
        else {
            for (size_t i = 0; i < times.size(); ++i) {
                out_quat[i].mTime = CONVERT_FBX_TIME(times[i]) * anim_fps;
                out_quat[i].mValue = def_rotation;
            }
        }

        if (scaling.size()) {
            InterpolateKeys(out_scale, times, scaling, true, maxTime, minTime);
        }
        else {
            for (size_t i = 0; i < times.size(); ++i) {
                out_scale[i].mTime = CONVERT_FBX_TIME(times[i]) * anim_fps;
                out_scale[i].mValue = def_scale;
            }
        }

        if (translation.size()) {
            InterpolateKeys(out_translation, times, translation, false, maxTime, minTime);
        }
        else {
            for (size_t i = 0; i < times.size(); ++i) {
                out_translation[i].mTime = CONVERT_FBX_TIME(times[i]) * anim_fps;
                out_translation[i].mValue = def_translate;
            }
        }

        const size_t count = times.size();
        for (size_t i = 0; i < count; ++i) {
            aiQuaternion& r = out_quat[i].mValue;
            aiVector3D& s = out_scale[i].mValue;
            aiVector3D& t = out_translation[i].mValue;

            aiMatrix4x4 mat, temp;
            aiMatrix4x4::Translation(t, mat);
            mat *= aiMatrix4x4( r.GetMatrix() );
            mat *= aiMatrix4x4::Scaling(s, temp);

            mat.Decompose(s, r, t);
        }
    }


    // ------------------------------------------------------------------------------------------------
    // euler xyz -> quat
    aiQuaternion EulerToQuaternion(const aiVector3D& rot, Model::RotOrder order)
    {
        aiMatrix4x4 m;
        GetRotationMatrix(order, rot, m);

        return aiQuaternion(aiMatrix3x3(m));
    }


    // ------------------------------------------------------------------------------------------------
    void ConvertScaleKeys(aiNodeAnim* na, const std::vector<const AnimationCurveNode*>& nodes, const LayerMap& /*layers*/,
        int64_t start, int64_t stop,
        double& maxTime,
        double& minTime)
    {
        ai_assert(nodes.size());

        // XXX for now, assume scale should be blended geometrically (i.e. two
        // layers should be multiplied with each other). There is a FBX
        // property in the layer to specify the behaviour, though.

        const KeyFrameListList& inputs = GetKeyframeList(nodes, start, stop);
        const KeyTimeList& keys = GetKeyTimeList(inputs);

        na->mNumScalingKeys = static_cast<unsigned int>(keys.size());
        na->mScalingKeys = new aiVectorKey[keys.size()];
        if (keys.size() > 0)
            InterpolateKeys(na->mScalingKeys, keys, inputs, true, maxTime, minTime);
    }


    // ------------------------------------------------------------------------------------------------
    void ConvertTranslationKeys(aiNodeAnim* na, const std::vector<const AnimationCurveNode*>& nodes,
        const LayerMap& /*layers*/,
        int64_t start, int64_t stop,
        double& maxTime,
        double& minTime)
    {
        ai_assert(nodes.size());

        // XXX see notes in ConvertScaleKeys()
        const KeyFrameListList& inputs = GetKeyframeList(nodes, start, stop);
        const KeyTimeList& keys = GetKeyTimeList(inputs);

        na->mNumPositionKeys = static_cast<unsigned int>(keys.size());
        na->mPositionKeys = new aiVectorKey[keys.size()];
        if (keys.size() > 0)
            InterpolateKeys(na->mPositionKeys, keys, inputs, false, maxTime, minTime);
    }


    // ------------------------------------------------------------------------------------------------
    void ConvertRotationKeys(aiNodeAnim* na, const std::vector<const AnimationCurveNode*>& nodes,
        const LayerMap& /*layers*/,
        int64_t start, int64_t stop,
        double& maxTime,
        double& minTime,
        Model::RotOrder order)
    {
        ai_assert(nodes.size());

        // XXX see notes in ConvertScaleKeys()
        const std::vector< KeyFrameList >& inputs = GetKeyframeList(nodes, start, stop);
        const KeyTimeList& keys = GetKeyTimeList(inputs);

        na->mNumRotationKeys = static_cast<unsigned int>(keys.size());
        na->mRotationKeys = new aiQuatKey[keys.size()];
        if (keys.size() > 0)
            InterpolateKeys(na->mRotationKeys, keys, inputs, false, maxTime, minTime, order);
    }


    // ------------------------------------------------------------------------------------------------
    // copy generated meshes, animations, lights, cameras and textures to the output scene
    void TransferDataToScene()
    {
        ai_assert(!out->mMeshes && !out->mNumMeshes);

        // note: the trailing () ensures initialization with NULL - not
        // many C++ users seem to know this, so pointing it out to avoid
        // confusion why this code works.

        if(meshes.size()) {
            out->mMeshes = new aiMesh*[meshes.size()]();
            out->mNumMeshes = static_cast<unsigned int>(meshes.size());

            std::swap_ranges(meshes.begin(),meshes.end(),out->mMeshes);
        }

        if(materials.size()) {
            out->mMaterials = new aiMaterial*[materials.size()]();
            out->mNumMaterials = static_cast<unsigned int>(materials.size());

            std::swap_ranges(materials.begin(),materials.end(),out->mMaterials);
        }

        if(animations.size()) {
            out->mAnimations = new aiAnimation*[animations.size()]();
            out->mNumAnimations = static_cast<unsigned int>(animations.size());

            std::swap_ranges(animations.begin(),animations.end(),out->mAnimations);
        }

        if(lights.size()) {
            out->mLights = new aiLight*[lights.size()]();
            out->mNumLights = static_cast<unsigned int>(lights.size());

            std::swap_ranges(lights.begin(),lights.end(),out->mLights);
        }

        if(cameras.size()) {
            out->mCameras = new aiCamera*[cameras.size()]();
            out->mNumCameras = static_cast<unsigned int>(cameras.size());

            std::swap_ranges(cameras.begin(),cameras.end(),out->mCameras);
        }
    }


private:

    // 0: not assigned yet, others: index is value - 1
    unsigned int defaultMaterialIndex;

    std::vector<aiMesh*> meshes;
    std::vector<aiMaterial*> materials;
    std::vector<aiAnimation*> animations;
    std::vector<aiLight*> lights;
    std::vector<aiCamera*> cameras;

    typedef std::map<const Material*, unsigned int> MaterialMap;
    MaterialMap materials_converted;

    typedef std::map<const Geometry*, std::vector<unsigned int> > MeshMap;
    MeshMap meshes_converted;

    // fixed node name -> which trafo chain components have animations?
    typedef std::map<std::string, unsigned int> NodeAnimBitMap;
    NodeAnimBitMap node_anim_chain_bits;

    // name -> has had its prefix_stripped?
    typedef std::map<std::string, bool> NodeNameMap;
    NodeNameMap node_names;

    typedef std::map<std::string, std::string> NameNameMap;
    NameNameMap renamed_nodes;

    double anim_fps;

    aiScene* const out;
    const FBX::Document& doc;
};

//} // !anon

// ------------------------------------------------------------------------------------------------
void ConvertToAssimpScene(aiScene* out, const Document& doc)
{
    Converter converter(out,doc);
}

} // !FBX
} // !Assimp

#endif