message: fix for default materials
diff: @@ -408,7 +408,9 @@ void GLTFData::createMaterials()
  ospMaterials.reserve(model.materials.size() + 1);
  // "default" material for glTF '-1' index (no material)
  - ospMaterials.emplace_back(createNode(fileName.name() + ":default", "obj"));
  + static int defMatNum = 0;
  + ospMaterials.emplace_back(createNode(
  + fileName.name() + std::to_string(defMatNum++) + ":default", "obj"));
  // Create materials (also sets textures to material params)
  for (const auto &material : model.materials) {
  