diff --git a/code/AssxmlExporter.cpp b/code/AssxmlExporter.cpp
index 9e8037649..bcf805501 100644
--- a/code/AssxmlExporter.cpp
+++ b/code/AssxmlExporter.cpp
@@ -67,6 +67,7 @@ namespace AssxmlExport  {
 
 // -----------------------------------------------------------------------------------
 static int ioprintf( IOStream * io, const char *format, ... ) {
+	using namespace std;
     if ( nullptr == io ) {
         return -1;
     }
@@ -77,7 +78,7 @@ static int ioprintf( IOStream * io, const char *format, ... ) {
     ::memset( sz, '\0', Size );
     va_list va;
     va_start( va, format );
-    int nSize = std::vsnprintf( sz, Size-1, format, va );
+    int nSize = vsnprintf( sz, Size-1, format, va );
     ai_assert( nSize < Size );
     va_end( va );
 
diff --git a/code/STEPFile.h b/code/STEPFile.h
index f97845dd8..252e75dbb 100644
--- a/code/STEPFile.h
+++ b/code/STEPFile.h
@@ -596,11 +596,6 @@ namespace STEP {
         LazyObject(DB& db, uint64_t id, uint64_t line, const char* type,const char* args);
         ~LazyObject();
 
-        LazyObject( LazyObject const& ) = delete;
-        LazyObject operator=( LazyObject const& ) = delete;
-        LazyObject( LazyObject && ) = delete;
-        LazyObject operator=( LazyObject  && ) = delete;
-
     public:
 
         Object& operator * () {
diff --git a/code/SceneCombiner.cpp b/code/SceneCombiner.cpp
index b56e2e601..5a138f809 100644
--- a/code/SceneCombiner.cpp
+++ b/code/SceneCombiner.cpp
@@ -1211,6 +1211,11 @@ void SceneCombiner::Copy     (aiNode** _dest, const aiNode* src)
     // and reallocate all arrays
     GetArrayCopy( dest->mMeshes, dest->mNumMeshes );
     CopyPtrArray( dest->mChildren, src->mChildren,dest->mNumChildren);
+
+	// need to set the mParent fields to the created aiNode.
+	for( unsigned int i = 0; i < dest->mNumChildren; i ++ ) {
+		dest->mChildren[i]->mParent = dest;
+	}
 }
 
 // ------------------------------------------------------------------------------------------------
diff --git a/code/SplitByBoneCountProcess.cpp b/code/SplitByBoneCountProcess.cpp
index 0e913932c..cbc60beec 100644
--- a/code/SplitByBoneCountProcess.cpp
+++ b/code/SplitByBoneCountProcess.cpp
@@ -90,7 +90,7 @@ void SplitByBoneCountProcess::Execute( aiScene* pScene)
 
     // early out
     bool isNecessary = false;
-    for( size_t a = 0; a < pScene->mNumMeshes; ++a)
+    for( unsigned int a = 0; a < pScene->mNumMeshes; ++a)
         if( pScene->mMeshes[a]->mNumBones > mMaxBoneCount )
             isNecessary = true;
 
@@ -107,7 +107,7 @@ void SplitByBoneCountProcess::Execute( aiScene* pScene)
     // build a new array of meshes for the scene
     std::vector<aiMesh*> meshes;
 
-    for( size_t a = 0; a < pScene->mNumMeshes; ++a)
+    for( unsigned int a = 0; a < pScene->mNumMeshes; ++a)
     {
         aiMesh* srcMesh = pScene->mMeshes[a];
 
@@ -118,9 +118,9 @@ void SplitByBoneCountProcess::Execute( aiScene* pScene)
         if( !newMeshes.empty() )
         {
             // store new meshes and indices of the new meshes
-            for( size_t b = 0; b < newMeshes.size(); ++b)
+            for( unsigned int b = 0; b < newMeshes.size(); ++b)
             {
-                mSubMeshIndices[a].push_back( meshes.size());
+                mSubMeshIndices[a].push_back( static_cast<unsigned int>(meshes.size()));
                 meshes.push_back( newMeshes[b]);
             }
 
@@ -130,13 +130,13 @@ void SplitByBoneCountProcess::Execute( aiScene* pScene)
         else
         {
             // Mesh is kept unchanged - store it's new place in the mesh array
-            mSubMeshIndices[a].push_back( meshes.size());
+            mSubMeshIndices[a].push_back( static_cast<unsigned int>(meshes.size()));
             meshes.push_back( srcMesh);
         }
     }
 
     // rebuild the scene's mesh array
-    pScene->mNumMeshes = meshes.size();
+    pScene->mNumMeshes = static_cast<unsigned int>(meshes.size());
     delete [] pScene->mMeshes;
     pScene->mMeshes = new aiMesh*[pScene->mNumMeshes];
     std::copy( meshes.begin(), meshes.end(), pScene->mMeshes);
@@ -157,33 +157,33 @@ void SplitByBoneCountProcess::SplitMesh( const aiMesh* pMesh, std::vector<aiMesh
 
     // necessary optimisation: build a list of all affecting bones for each vertex
     // TODO: (thom) maybe add a custom allocator here to avoid allocating tens of thousands of small arrays
-    typedef std::pair<size_t, float> BoneWeight;
+    typedef std::pair<unsigned int, float> BoneWeight;
     std::vector< std::vector<BoneWeight> > vertexBones( pMesh->mNumVertices);
-    for( size_t a = 0; a < pMesh->mNumBones; ++a)
+    for( unsigned int a = 0; a < pMesh->mNumBones; ++a)
     {
         const aiBone* bone = pMesh->mBones[a];
-        for( size_t b = 0; b < bone->mNumWeights; ++b)
+        for( unsigned int b = 0; b < bone->mNumWeights; ++b)
             vertexBones[ bone->mWeights[b].mVertexId ].push_back( BoneWeight( a, bone->mWeights[b].mWeight));
     }
 
-    size_t numFacesHandled = 0;
+    unsigned int numFacesHandled = 0;
     std::vector<bool> isFaceHandled( pMesh->mNumFaces, false);
     while( numFacesHandled < pMesh->mNumFaces )
     {
         // which bones are used in the current submesh
-        size_t numBones = 0;
+        unsigned int numBones = 0;
         std::vector<bool> isBoneUsed( pMesh->mNumBones, false);
         // indices of the faces which are going to go into this submesh
-        std::vector<size_t> subMeshFaces;
+        std::vector<unsigned int> subMeshFaces;
         subMeshFaces.reserve( pMesh->mNumFaces);
         // accumulated vertex count of all the faces in this submesh
-        size_t numSubMeshVertices = 0;
+        unsigned int numSubMeshVertices = 0;
         // a small local array of new bones for the current face. State of all used bones for that face
         // can only be updated AFTER the face is completely analysed. Thanks to imre for the fix.
-        std::vector<size_t> newBonesAtCurrentFace;
+        std::vector<unsigned int> newBonesAtCurrentFace;
 
         // add faces to the new submesh as long as all bones affecting the faces' vertices fit in the limit
-        for( size_t a = 0; a < pMesh->mNumFaces; ++a)
+        for( unsigned int a = 0; a < pMesh->mNumFaces; ++a)
         {
             // skip if the face is already stored in a submesh
             if( isFaceHandled[a] )
@@ -191,12 +191,12 @@ void SplitByBoneCountProcess::SplitMesh( const aiMesh* pMesh, std::vector<aiMesh
 
             const aiFace& face = pMesh->mFaces[a];
             // check every vertex if its bones would still fit into the current submesh
-            for( size_t b = 0; b < face.mNumIndices; ++b )
+            for( unsigned int b = 0; b < face.mNumIndices; ++b )
             {
                 const std::vector<BoneWeight>& vb = vertexBones[face.mIndices[b]];
-                for( size_t c = 0; c < vb.size(); ++c)
+                for( unsigned int c = 0; c < vb.size(); ++c)
                 {
-                    size_t boneIndex = vb[c].first;
+                    unsigned int boneIndex = vb[c].first;
                     // if the bone is already used in this submesh, it's ok
                     if( isBoneUsed[boneIndex] )
                         continue;
@@ -214,7 +214,7 @@ void SplitByBoneCountProcess::SplitMesh( const aiMesh* pMesh, std::vector<aiMesh
             // mark all new bones as necessary
             while( !newBonesAtCurrentFace.empty() )
             {
-                size_t newIndex = newBonesAtCurrentFace.back();
+                unsigned int newIndex = newBonesAtCurrentFace.back();
                 newBonesAtCurrentFace.pop_back(); // this also avoids the deallocation which comes with a clear()
                 if( isBoneUsed[newIndex] )
                     continue;
@@ -242,7 +242,7 @@ void SplitByBoneCountProcess::SplitMesh( const aiMesh* pMesh, std::vector<aiMesh
 
         // create all the arrays for this mesh if the old mesh contained them
         newMesh->mNumVertices = numSubMeshVertices;
-        newMesh->mNumFaces = subMeshFaces.size();
+        newMesh->mNumFaces = static_cast<unsigned int>(subMeshFaces.size());
         newMesh->mVertices = new aiVector3D[newMesh->mNumVertices];
         if( pMesh->HasNormals() )
             newMesh->mNormals = new aiVector3D[newMesh->mNumVertices];
@@ -251,13 +251,13 @@ void SplitByBoneCountProcess::SplitMesh( const aiMesh* pMesh, std::vector<aiMesh
             newMesh->mTangents = new aiVector3D[newMesh->mNumVertices];
             newMesh->mBitangents = new aiVector3D[newMesh->mNumVertices];
         }
-        for( size_t a = 0; a < AI_MAX_NUMBER_OF_TEXTURECOORDS; ++a )
+        for( unsigned int a = 0; a < AI_MAX_NUMBER_OF_TEXTURECOORDS; ++a )
         {
             if( pMesh->HasTextureCoords( a) )
                 newMesh->mTextureCoords[a] = new aiVector3D[newMesh->mNumVertices];
             newMesh->mNumUVComponents[a] = pMesh->mNumUVComponents[a];
         }
-        for( size_t a = 0; a < AI_MAX_NUMBER_OF_COLOR_SETS; ++a )
+        for( unsigned int a = 0; a < AI_MAX_NUMBER_OF_COLOR_SETS; ++a )
         {
             if( pMesh->HasVertexColors( a) )
                 newMesh->mColors[a] = new aiColor4D[newMesh->mNumVertices];
@@ -265,9 +265,9 @@ void SplitByBoneCountProcess::SplitMesh( const aiMesh* pMesh, std::vector<aiMesh
 
         // and copy over the data, generating faces with linear indices along the way
         newMesh->mFaces = new aiFace[subMeshFaces.size()];
-        size_t nvi = 0; // next vertex index
-        std::vector<size_t> previousVertexIndices( numSubMeshVertices, std::numeric_limits<size_t>::max()); // per new vertex: its index in the source mesh
-        for( size_t a = 0; a < subMeshFaces.size(); ++a )
+        unsigned int nvi = 0; // next vertex index
+        std::vector<unsigned int> previousVertexIndices( numSubMeshVertices, std::numeric_limits<unsigned int>::max()); // per new vertex: its index in the source mesh
+        for( unsigned int a = 0; a < subMeshFaces.size(); ++a )
         {
             const aiFace& srcFace = pMesh->mFaces[subMeshFaces[a]];
             aiFace& dstFace = newMesh->mFaces[a];
@@ -275,9 +275,9 @@ void SplitByBoneCountProcess::SplitMesh( const aiMesh* pMesh, std::vector<aiMesh
             dstFace.mIndices = new unsigned int[dstFace.mNumIndices];
 
             // accumulate linearly all the vertices of the source face
-            for( size_t b = 0; b < dstFace.mNumIndices; ++b )
+            for( unsigned int b = 0; b < dstFace.mNumIndices; ++b )
             {
-                size_t srcIndex = srcFace.mIndices[b];
+                unsigned int srcIndex = srcFace.mIndices[b];
                 dstFace.mIndices[b] = nvi;
                 previousVertexIndices[nvi] = srcIndex;
 
@@ -289,12 +289,12 @@ void SplitByBoneCountProcess::SplitMesh( const aiMesh* pMesh, std::vector<aiMesh
                     newMesh->mTangents[nvi] = pMesh->mTangents[srcIndex];
                     newMesh->mBitangents[nvi] = pMesh->mBitangents[srcIndex];
                 }
-                for( size_t c = 0; c < AI_MAX_NUMBER_OF_TEXTURECOORDS; ++c )
+                for( unsigned int c = 0; c < AI_MAX_NUMBER_OF_TEXTURECOORDS; ++c )
                 {
                     if( pMesh->HasTextureCoords( c) )
                         newMesh->mTextureCoords[c][nvi] = pMesh->mTextureCoords[c][srcIndex];
                 }
-                for( size_t c = 0; c < AI_MAX_NUMBER_OF_COLOR_SETS; ++c )
+                for( unsigned int c = 0; c < AI_MAX_NUMBER_OF_COLOR_SETS; ++c )
                 {
                     if( pMesh->HasVertexColors( c) )
                         newMesh->mColors[c][nvi] = pMesh->mColors[c][srcIndex];
@@ -310,8 +310,8 @@ void SplitByBoneCountProcess::SplitMesh( const aiMesh* pMesh, std::vector<aiMesh
         newMesh->mNumBones = 0;
         newMesh->mBones = new aiBone*[numBones];
 
-        std::vector<size_t> mappedBoneIndex( pMesh->mNumBones, std::numeric_limits<size_t>::max());
-        for( size_t a = 0; a < pMesh->mNumBones; ++a )
+        std::vector<unsigned int> mappedBoneIndex( pMesh->mNumBones, std::numeric_limits<unsigned int>::max());
+        for( unsigned int a = 0; a < pMesh->mNumBones; ++a )
         {
             if( !isBoneUsed[a] )
                 continue;
@@ -329,21 +329,21 @@ void SplitByBoneCountProcess::SplitMesh( const aiMesh* pMesh, std::vector<aiMesh
         ai_assert( newMesh->mNumBones == numBones );
 
         // iterate over all new vertices and count which bones affected its old vertex in the source mesh
-        for( size_t a = 0; a < numSubMeshVertices; ++a )
+        for( unsigned int a = 0; a < numSubMeshVertices; ++a )
         {
-            size_t oldIndex = previousVertexIndices[a];
+            unsigned int oldIndex = previousVertexIndices[a];
             const std::vector<BoneWeight>& bonesOnThisVertex = vertexBones[oldIndex];
 
-            for( size_t b = 0; b < bonesOnThisVertex.size(); ++b )
+            for( unsigned int b = 0; b < bonesOnThisVertex.size(); ++b )
             {
-                size_t newBoneIndex = mappedBoneIndex[ bonesOnThisVertex[b].first ];
-                if( newBoneIndex != std::numeric_limits<size_t>::max() )
+                unsigned int newBoneIndex = mappedBoneIndex[ bonesOnThisVertex[b].first ];
+                if( newBoneIndex != std::numeric_limits<unsigned int>::max() )
                     newMesh->mBones[newBoneIndex]->mNumWeights++;
             }
         }
 
         // allocate all bone weight arrays accordingly
-        for( size_t a = 0; a < newMesh->mNumBones; ++a )
+        for( unsigned int a = 0; a < newMesh->mNumBones; ++a )
         {
             aiBone* bone = newMesh->mBones[a];
             ai_assert( bone->mNumWeights > 0 );
@@ -352,18 +352,18 @@ void SplitByBoneCountProcess::SplitMesh( const aiMesh* pMesh, std::vector<aiMesh
         }
 
         // now copy all the bone vertex weights for all the vertices which made it into the new submesh
-        for( size_t a = 0; a < numSubMeshVertices; ++a)
+        for( unsigned int a = 0; a < numSubMeshVertices; ++a)
         {
             // find the source vertex for it in the source mesh
-            size_t previousIndex = previousVertexIndices[a];
+            unsigned int previousIndex = previousVertexIndices[a];
             // these bones were affecting it
             const std::vector<BoneWeight>& bonesOnThisVertex = vertexBones[previousIndex];
             // all of the bones affecting it should be present in the new submesh, or else
             // the face it comprises shouldn't be present
-            for( size_t b = 0; b < bonesOnThisVertex.size(); ++b)
+            for( unsigned int b = 0; b < bonesOnThisVertex.size(); ++b)
             {
-                size_t newBoneIndex = mappedBoneIndex[ bonesOnThisVertex[b].first ];
-                ai_assert( newBoneIndex != std::numeric_limits<size_t>::max() );
+                unsigned int newBoneIndex = mappedBoneIndex[ bonesOnThisVertex[b].first ];
+                ai_assert( newBoneIndex != std::numeric_limits<unsigned int>::max() );
                 aiVertexWeight* dstWeight = newMesh->mBones[newBoneIndex]->mWeights + newMesh->mBones[newBoneIndex]->mNumWeights;
                 newMesh->mBones[newBoneIndex]->mNumWeights++;
 
@@ -383,22 +383,22 @@ void SplitByBoneCountProcess::UpdateNode( aiNode* pNode) const
     // rebuild the node's mesh index list
     if( pNode->mNumMeshes > 0 )
     {
-        std::vector<size_t> newMeshList;
-        for( size_t a = 0; a < pNode->mNumMeshes; ++a)
+        std::vector<unsigned int> newMeshList;
+        for( unsigned int a = 0; a < pNode->mNumMeshes; ++a)
         {
-            size_t srcIndex = pNode->mMeshes[a];
-            const std::vector<size_t>& replaceMeshes = mSubMeshIndices[srcIndex];
+            unsigned int srcIndex = pNode->mMeshes[a];
+            const std::vector<unsigned int>& replaceMeshes = mSubMeshIndices[srcIndex];
             newMeshList.insert( newMeshList.end(), replaceMeshes.begin(), replaceMeshes.end());
         }
 
         delete pNode->mMeshes;
-        pNode->mNumMeshes = newMeshList.size();
+        pNode->mNumMeshes = static_cast<unsigned int>(newMeshList.size());
         pNode->mMeshes = new unsigned int[pNode->mNumMeshes];
         std::copy( newMeshList.begin(), newMeshList.end(), pNode->mMeshes);
     }
 
     // do that also recursively for all children
-    for( size_t a = 0; a < pNode->mNumChildren; ++a )
+    for( unsigned int a = 0; a < pNode->mNumChildren; ++a )
     {
         UpdateNode( pNode->mChildren[a]);
     }
diff --git a/code/SplitByBoneCountProcess.h b/code/SplitByBoneCountProcess.h
index f4816952d..39f47d043 100644
--- a/code/SplitByBoneCountProcess.h
+++ b/code/SplitByBoneCountProcess.h
@@ -101,7 +101,7 @@ public:
     size_t mMaxBoneCount;
 
     /// Per mesh index: Array of indices of the new submeshes.
-    std::vector< std::vector<size_t> > mSubMeshIndices;
+    std::vector< std::vector<unsigned int> > mSubMeshIndices;
 };
 
 } // end of namespace Assimp
diff --git a/code/glTFAsset.h b/code/glTFAsset.h
index be3c3e756..c7045a609 100644
--- a/code/glTFAsset.h
+++ b/code/glTFAsset.h
@@ -759,6 +759,7 @@ namespace glTF
         virtual void WriteObjects(AssetWriter& writer) = 0;
     };
 
+
     template<class T>
     class LazyDict;
 
@@ -766,6 +767,7 @@ namespace glTF
     template<class T>
     void WriteLazyDict(LazyDict<T>& d, AssetWriter& w);
 
+
     //! Manages lazy loading of the glTF top-level objects, and keeps a reference to them by ID
     //! It is the owner the loaded objects, so when it is destroyed it also deletes them
     template<class T>
diff --git a/code/glTFAssetWriter.inl b/code/glTFAssetWriter.inl
index 0e51ebd94..0fa8556c0 100644
--- a/code/glTFAssetWriter.inl
+++ b/code/glTFAssetWriter.inl
@@ -305,7 +305,7 @@ namespace glTF {
     }
 
 
-    AssetWriter::AssetWriter(Asset& a)
+    inline AssetWriter::AssetWriter(Asset& a)
         : mDoc()
         , mAsset(a)
         , mAl(mDoc.GetAllocator())
@@ -326,7 +326,7 @@ namespace glTF {
         }
     }
 
-    void AssetWriter::WriteFile(const char* path)
+    inline void AssetWriter::WriteFile(const char* path)
     {
         bool isBinary = mAsset.extensionsUsed.KHR_binary_glTF;
 
@@ -363,7 +363,7 @@ namespace glTF {
         }
     }
 
-    void AssetWriter::WriteBinaryData(IOStream* outfile, size_t sceneLength)
+    inline void AssetWriter::WriteBinaryData(IOStream* outfile, size_t sceneLength)
     {
         //
         // write the body data
@@ -413,7 +413,7 @@ namespace glTF {
     }
 
     
-    void AssetWriter::WriteMetadata()
+    inline void AssetWriter::WriteMetadata()
     {
         Value asset;
         asset.SetObject();
@@ -425,7 +425,7 @@ namespace glTF {
         mDoc.AddMember("asset", asset, mAl);
     }
 
-    void AssetWriter::WriteExtensionsUsed()
+    inline void AssetWriter::WriteExtensionsUsed()
     {
         Value exts;
         exts.SetArray();
diff --git a/code/glTFExporter.cpp b/code/glTFExporter.cpp
index 222947add..ca606ecdc 100644
--- a/code/glTFExporter.cpp
+++ b/code/glTFExporter.cpp
@@ -44,6 +44,7 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifndef ASSIMP_BUILD_NO_GLTF_EXPORTER
 
 #include "glTFExporter.h"
+
 #include "Exceptional.h"
 #include "StringComparison.h"
 #include "ByteSwapper.h"
@@ -54,7 +55,6 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include <assimp/material.h>
 #include <assimp/scene.h>
 
-#include <memory>
 #include <memory>
 
 #include "glTFAssetWriter.h"
diff --git a/code/glTFImporter.cpp b/code/glTFImporter.cpp
index fa730ddd1..a17076d63 100644
--- a/code/glTFImporter.cpp
+++ b/code/glTFImporter.cpp
@@ -53,6 +53,8 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include "MakeVerboseFormat.h"
 
 #include "glTFAsset.h"
+// This is included here so WriteLazyDict<T>'s definition is found.
+#include "glTFAssetWriter.h"
 
 using namespace Assimp;
 using namespace glTF;
diff --git a/test/regression/db.zip b/test/regression/db.zip
index 62a76956f..fba468a7b 100644
Binary files a/test/regression/db.zip and b/test/regression/db.zip differ