message: fixed importOBJ material creation
diff: @@ -92,6 +92,11 @@ namespace ospray {
  auto sgMaterials =
  createNode("materialList", "MaterialList")->nodeAs<MaterialList>();
  + if (mats.empty()) {
  + sgMaterials->push_back(createNode("default", "Material")->nodeAs<Material>());
  + return sgMaterials;
  + }
  +
  for (auto &mat : mats) {
  auto matNodePtr = createNode(mat.name, "Material")->nodeAs<Material>();
  auto &matNode = *matNodePtr;
  