I have been testing Sketchfab for reviewing a home I designed using SweetHome3D (which is free and awesome by the way)
The navigation in Sketchfab VR is a bit basic with the "click to teleport to a spot you focus", but in general it works for any one-room scenarios or open areas.
However, a normal house model has walls and closed doors creating a sealed box. In regular orbit and first person mode I can just go through any wall. However, in VR I cannot get in and out of the rooms. The only workaround I found is that I have to take off the VR, change the initial position in the VR settings of the model on my laptop, and reload the WebVR page again.
It would be great to have a way to move through walls and doors! One option I have seen in the obj2vr play store app that works fairly well is an automatic walking forward mode at a slow speed that can be turned on and off with the google cardboard button.