Since I did not work much on the project “Showroom” ( see Circular control used for walkable areas control)
for a while, an update from r116 to r121 was due. Only the following files were exchanged (from 116 to 121).
<script src="js/three.min.121.js"></script>
<script src="js/Reflector.121.js"></script>
<script src="js/GLTFLoader.121.js"></script>
<script src="js/OBJLoader.121.js"></script>
<script src="js/MTLLoader.121.js"></script>
So far everything is going well. But an obj model remains dark (staircase). Another one (flower) will be presented in a proper way.
Both Obj models are displayed correctly in the Windows 3D-Viewer.
Besides Gltf (girl) I have planned Obj, because there are some free available ones.
Are there differences between 116 and 121 in the use of Obj? 
