Check out this Unity (HTML 5 and WebGL) compiled Web 3D model viewer I created for Calibre Consulting:

http://bimwerx.nz/unity/sample/sample.html

(Use Chrome for best results)

The model was developed using Revit 2017, then exported to 3DS Max, and finally to Unity. I added a few menu components and some navigation scripts.

Click on the "About Viewer" button for instructions:

The model might take a few seconds to initialize, taking up to 10 seconds before starting, and should look like this after loading: