Thanks for the feedback @mrchlblng! I don't really have samples for now, because the iv format is rarely used by us outside FreeCAD. Internally in FreeCAD, it works like this: All the geometry is solid Brep geometry. The FreeCAD 3D view itself is an OpenInventor viewer (built with Coin3D). So in order to show the brep geometry on screen, each object outputs an openinventor mesh representation of itself. It is that representation that the sketchfab exporter uses to build the exported iv file.
So what comes to sketchfab is actually a pretty faithful representation of the FreeCAD 3D view, that's really interesting. I think actually the way sketchfab handles it is pretty good, even the lines are rendered, I'll test some more tech stuff later on, like dimensions, etc.
We need to test more, but if the freecad community embraces and starts using the exporter, we should get more soon. I'll tell everyone to report when an iv file gives problems.
About metadata & indicating the source, how does that work now? In API v1 there was a "source" keyword that you could provide. This doesn't seem to exist anymore in v3? The thing is, FreeCAD will allow to upload in several formats (obj, iv, dae, etc) depending on what the user prefers (obj will give better control over materials, while iv will give a more faithful representation of the freecad 3d view, etc). So what would be the best way to notify you guys that this was exported from FreeCAD?