I did'n find where to send some improvement suggestion so I will put it here.
I use for hobby sketchfab but as Surveyor very often I create some 3D model for clients, designer, architect... and with some extra function i 'm sure I would be able to use sketchfab as professional deliverable.
We are creating some 3D pdf for them and the big advantage is the fact they have the possibility to turn on/off the layer in the 3D pdf and extract dimensions from it. But some of our client can't open it due to software.
For example if i model the external/ internal of a building and publish it in sketchfab I would want to be able to turn off the room. Also to be able to extract some dimension of windows.
Happy to send an example to sketchfab developer team.