Expose the original OBJ illum model as a material property.

code/AssetLib/Obj/ObjFileImporter.cpp

@@ -605,6 +605,9 @@ void ObjFileImporter::createMaterials(const ObjFile::Model *pModel, aiScene *pSc
 
         mat->AddProperty<int>(&sm, 1, AI_MATKEY_SHADING_MODEL);
 
+        // Preserve the original illum value
+        mat->AddProperty<int>(&pCurrentMaterial->illumination_model, 1, AI_MATKEY_OBJ_ILLUM);
+
         // Adding material colors
         mat->AddProperty(&pCurrentMaterial->ambient, 1, AI_MATKEY_COLOR_AMBIENT);
         mat->AddProperty(&pCurrentMaterial->diffuse, 1, AI_MATKEY_COLOR_DIFFUSE);

include/assimp/ObjMaterial.h

@@ -53,6 +53,13 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #include <assimp/material.h>
 
+// ---------------------------------------------------------------------------
+
+// the original illum property
+#define AI_MATKEY_OBJ_ILLUM "$mat.illum", 0, 0
+
+// ---------------------------------------------------------------------------
+
 // ---------------------------------------------------------------------------
 // Pure key names for all obj texture-related properties
 //! @cond MATS_DOC_FULL