This announcement is out of date, and some information is deprecated. You can find up-to-date information on the Material Editor in our Help Center.

Following the new material editor features, here is a video demo of how to set up multiple UV channel from 3ds Max to Sketchfab, kindly provided by Revel:
And the related model:
Thanks to Revel, and feel free to reach out and send us your own video tips and walkthroughs that you think might be useful for other users!