diff --git a/code/AssetLib/Obj/ObjFileData.h b/code/AssetLib/Obj/ObjFileData.h
index 3d504d0bb..0dd13f545 100644
--- a/code/AssetLib/Obj/ObjFileData.h
+++ b/code/AssetLib/Obj/ObjFileData.h
@@ -47,6 +47,7 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include <assimp/types.h>
 #include <map>
 #include <vector>
+#include "Common/Maybe.h"
 
 namespace Assimp {
 namespace ObjFile {
@@ -183,15 +184,15 @@ struct Material {
     aiColor3D transparent;
 
     //! PBR Roughness
-    ai_real roughness;
+    Maybe<ai_real> roughness;
     //! PBR Metallic
-    ai_real metallic;
+    Maybe<ai_real> metallic;
     //! PBR Metallic
-    aiColor3D sheen;
+    Maybe<aiColor3D> sheen;
     //! PBR Clearcoat Thickness
-    ai_real clearcoat_thickness;
+    Maybe<ai_real> clearcoat_thickness;
     //! PBR Clearcoat Rougness
-    ai_real clearcoat_roughness;
+    Maybe<ai_real> clearcoat_roughness;
     //! PBR Anisotropy
     ai_real anisotropy;
 
@@ -206,11 +207,11 @@ struct Material {
             illumination_model(1),
             ior(ai_real(1.0)),
             transparent(ai_real(1.0), ai_real(1.0), ai_real(1.0)),
-            roughness(ai_real(1.0)),
-            metallic(ai_real(0.0)),
-            sheen(ai_real(1.0), ai_real(1.0), ai_real(1.0)),
-            clearcoat_thickness(ai_real(0.0)),
-            clearcoat_roughness(ai_real(0.0)),
+            roughness(),
+            metallic(),
+            sheen(),
+            clearcoat_thickness(),
+            clearcoat_roughness(),
             anisotropy(ai_real(0.0)),
             bump_multiplier(ai_real(1.0)) {
         std::fill_n(clamp, static_cast<unsigned int>(TextureTypeCount), false);
diff --git a/code/AssetLib/Obj/ObjFileImporter.cpp b/code/AssetLib/Obj/ObjFileImporter.cpp
index 68fdb2172..429c6ea9d 100644
--- a/code/AssetLib/Obj/ObjFileImporter.cpp
+++ b/code/AssetLib/Obj/ObjFileImporter.cpp
@@ -616,11 +616,16 @@ void ObjFileImporter::createMaterials(const ObjFile::Model *pModel, aiScene *pSc
         mat->AddProperty(&pCurrentMaterial->shineness, 1, AI_MATKEY_SHININESS);
         mat->AddProperty(&pCurrentMaterial->alpha, 1, AI_MATKEY_OPACITY);
         mat->AddProperty(&pCurrentMaterial->transparent, 1, AI_MATKEY_COLOR_TRANSPARENT);
-        mat->AddProperty(&pCurrentMaterial->roughness, 1, AI_MATKEY_ROUGHNESS_FACTOR);
-        mat->AddProperty(&pCurrentMaterial->metallic, 1, AI_MATKEY_METALLIC_FACTOR);
-        mat->AddProperty(&pCurrentMaterial->sheen, 1, AI_MATKEY_SHEEN_COLOR_FACTOR);
-        mat->AddProperty(&pCurrentMaterial->clearcoat_thickness, 1, AI_MATKEY_CLEARCOAT_FACTOR);
-        mat->AddProperty(&pCurrentMaterial->clearcoat_roughness, 1, AI_MATKEY_CLEARCOAT_ROUGHNESS_FACTOR);
+        if (pCurrentMaterial->roughness)
+            mat->AddProperty(&pCurrentMaterial->roughness.Get(), 1, AI_MATKEY_ROUGHNESS_FACTOR);
+        if (pCurrentMaterial->metallic)
+            mat->AddProperty(&pCurrentMaterial->metallic.Get(), 1, AI_MATKEY_METALLIC_FACTOR);
+        if (pCurrentMaterial->sheen)
+            mat->AddProperty(&pCurrentMaterial->sheen.Get(), 1, AI_MATKEY_SHEEN_COLOR_FACTOR);
+        if (pCurrentMaterial->clearcoat_thickness)
+            mat->AddProperty(&pCurrentMaterial->clearcoat_thickness.Get(), 1, AI_MATKEY_CLEARCOAT_FACTOR);
+        if (pCurrentMaterial->clearcoat_roughness)
+            mat->AddProperty(&pCurrentMaterial->clearcoat_roughness.Get(), 1, AI_MATKEY_CLEARCOAT_ROUGHNESS_FACTOR);
         mat->AddProperty(&pCurrentMaterial->anisotropy, 1, AI_MATKEY_ANISOTROPY_FACTOR);
 
         // Adding refraction index
diff --git a/code/AssetLib/Obj/ObjFileMtlImporter.cpp b/code/AssetLib/Obj/ObjFileMtlImporter.cpp
index bb70a5ed0..a73277701 100644
--- a/code/AssetLib/Obj/ObjFileMtlImporter.cpp
+++ b/code/AssetLib/Obj/ObjFileMtlImporter.cpp
@@ -205,7 +205,7 @@ void ObjFileMtlImporter::load() {
                         break;
                     case 's':
                         ++m_DataIt;
-                        getColorRGBA(&m_pModel->m_pCurrentMaterial->sheen);
+                        getColorRGBA(m_pModel->m_pCurrentMaterial->sheen);
                         break;
                     case 'c':
                         ++m_DataIt;
@@ -268,6 +268,12 @@ void ObjFileMtlImporter::getColorRGBA(aiColor3D *pColor) {
     pColor->b = b;
 }
 
+void ObjFileMtlImporter::getColorRGBA(Maybe<aiColor3D> &value) {
+    aiColor3D v;
+    getColorRGBA(&v);
+    value = Maybe<aiColor3D>(v);
+}
+
 // -------------------------------------------------------------------
 //  Loads the kind of illumination model.
 void ObjFileMtlImporter::getIlluminationModel(int &illum_model) {
@@ -275,6 +281,7 @@ void ObjFileMtlImporter::getIlluminationModel(int &illum_model) {
     illum_model = atoi(&m_buffer[0]);
 }
 
+
 // -------------------------------------------------------------------
 //  Loads a single float value.
 void ObjFileMtlImporter::getFloatValue(ai_real &value) {
@@ -284,10 +291,19 @@ void ObjFileMtlImporter::getFloatValue(ai_real &value) {
         value = 0.0f;
         return;
     }
-    
+
     value = (ai_real)fast_atof(&m_buffer[0]);
 }
 
+void ObjFileMtlImporter::getFloatValue(Maybe<ai_real> &value) {
+    m_DataIt = CopyNextWord<DataArrayIt>(m_DataIt, m_DataItEnd, &m_buffer[0], BUFFERSIZE);
+    size_t len = std::strlen(&m_buffer[0]);
+    if (len)
+        value = Maybe<ai_real>(fast_atof(&m_buffer[0]));
+    else
+        value = Maybe<ai_real>();
+}
+
 // -------------------------------------------------------------------
 //  Creates a material from loaded data.
 void ObjFileMtlImporter::createMaterial() {
diff --git a/code/AssetLib/Obj/ObjFileMtlImporter.h b/code/AssetLib/Obj/ObjFileMtlImporter.h
index cda7415e6..6e73cf45c 100644
--- a/code/AssetLib/Obj/ObjFileMtlImporter.h
+++ b/code/AssetLib/Obj/ObjFileMtlImporter.h
@@ -43,6 +43,7 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include <assimp/defs.h>
 #include <string>
 #include <vector>
+#include "Common/Maybe.h"
 
 struct aiColor3D;
 struct aiString;
@@ -81,10 +82,12 @@ private:
     void load();
     /// Get color data.
     void getColorRGBA(aiColor3D *pColor);
+    void getColorRGBA(Maybe<aiColor3D> &value);
     /// Get illumination model from loaded data
     void getIlluminationModel(int &illum_model);
     /// Gets a float value from data.
     void getFloatValue(ai_real &value);
+    void getFloatValue(Maybe<ai_real> &value);
     /// Creates a new material from loaded data.
     void createMaterial();
     /// Get texture name from loaded data.
diff --git a/code/CMakeLists.txt b/code/CMakeLists.txt
index 2eff6117f..5b08c0f37 100644
--- a/code/CMakeLists.txt
+++ b/code/CMakeLists.txt
@@ -182,6 +182,7 @@ SET( Common_SRCS
   Common/DefaultIOSystem.cpp
   Common/ZipArchiveIOSystem.cpp
   Common/PolyTools.h
+  Common/Maybe.h
   Common/Importer.cpp
   Common/IFF.h
   Common/SGSpatialSort.cpp
diff --git a/code/Common/Maybe.h b/code/Common/Maybe.h
new file mode 100644
index 000000000..3eb2e1d97
--- /dev/null
+++ b/code/Common/Maybe.h
@@ -0,0 +1,29 @@
+#pragma once
+#include <assimp/ai_assert.h>
+
+template <typename T>
+struct Maybe {
+private:
+    T _val;
+    bool _valid;
+
+public:
+    Maybe() :
+            _valid(false) {}
+
+    explicit Maybe(const T &val) :
+            _val(val), _valid(true) {
+    }
+
+    operator bool() const {
+        return _valid;
+    }
+
+    const T &Get() const {
+        ai_assert(_valid);
+        return _val;
+    }
+
+private:
+    Maybe &operator&() = delete;
+};