Why Problems Viewing 3D PDF in a Web Browser?

Why Problems Viewing 3D PDF in a Web Browser?

This is a subject the industry should improve, we see that Adobe is struggling to get major browser vendors to respect ISO PDF standards. Adobe used to provide browser plugins, but modern browsers have withdrawn this API. Main Issue Experienced by Users:
a) Sometimes users open a 3D PDF in a tool which shows just the 2D parts without 3D.
b) Sometimes users open a 3D PDF in Adobe Reader and see a warning and no initial 3D.
Advice from Adobe: How to enable Adobe to open 3D immediately
How to configure Acrobat to open PDFs in a browser
Summary of issues with various web browsers showing PDFs