message: obj loader supports multi models now in sg
diff: @@ -163,6 +163,7 @@ namespace ospray {
  std::vector<vec3f> vn;
  std::vector<vec2f> vt;
  std::vector<std::vector<Vertex> > curGroup;
  + std::string curGroupName={""};
  /*! Material handling. */
  std::shared_ptr<Material> curMaterial;
  @@ -225,6 +226,9 @@ namespace ospray {
  const char* token = trimEnd(line + strspn(line, " \t"));
  if (token[0] == 0) continue;
  + if (token[0] == 'g')
  + curGroupName = std::string(parseSep(token += 1));
  +
  /*! parse position */
  if (token[0] == 'v' && isSep(token[1]))
  { v.push_back(getVec3f(token += 2)); continue; }
  @@ -479,8 +483,9 @@ namespace ospray {
  if (curGroup.empty()) return;
  std::map<Vertex, uint32_t> vertexMap;
  + std::string name = fullPath.name()+"_"+curGroupName;
  //scenegraph
  - std::shared_ptr<TriangleMesh> mesh = std::static_pointer_cast<TriangleMesh>(createNode(fullPath.name(), "TriangleMesh").get());
  + std::shared_ptr<TriangleMesh> mesh = std::static_pointer_cast<TriangleMesh>(createNode(name, "TriangleMesh").get());
  world->add(mesh);
  mesh->vertex = std::make_shared<DataVector3f>();
  mesh->normal = std::make_shared<DataVector3f>();
  