[abenedik]

Yes, Assimp64 is not a .Net assembly (dll) but a a native dll (C++ project) so it cannot be added as a reference. But it needs to be available so that .net can load it - it is best to be in the same folder as exe. In this case the library will be automatically loaded. But if you want you can also put it into some other folder and then load the library with calling: AssimpWpfImporter.LoadAssimpNativeLibrary(assimp32Folder, assimp64Folder);