message: Don't create the plane as Instance
diff: @@ -237,13 +237,12 @@ static inline void addPlaneToScene(sg::Node& renderer)
  index->push_back(vec3i{1,2,3});
  index->setName("index");
  - auto &plane = world.createChild("plane", "Instance");
  - auto &mesh = plane.child("model").createChild("mesh", "TriangleMesh");
  + auto &plane = world.createChild("plane", "TriangleMesh");
  - auto sg_plane = mesh.nodeAs<sg::TriangleMesh>();
  + auto sg_plane = plane.nodeAs<sg::TriangleMesh>();
  sg_plane->add(position);
  sg_plane->add(index);
  - auto &planeMaterial = mesh["material"];
  + auto &planeMaterial = plane["material"];
  planeMaterial["Kd"] = vec3f(0.5f);
  planeMaterial["Ks"] = vec3f(0.1f);
  planeMaterial["Ns"] = 10.f;
  