We do have support for obj files by www.3dmr.eu
It is just beeing inovated. No OBJ any more but GLB.
Used by OSM2World and OSMgo.
F4map has it’s own 3D model (closed data)
There is an attempt for an 3D editor “in world”.
Stand alone or inside OSM2World may be.
There is a JOSM plugin for simple 3D, but not for GLB.
If the above code is running, it may be usable from JSOM to.