Thanks for sending me the file. This was a tough nut to crack. At first I believed the culprit was the Keyframe on the location, so I removed them. No luck.
I’ve figured there is some kind of parenting limit on Sketchfab, no matter how many times I un and reparented the head.
I came up with two solutions to prevent this in the future:
- Use of an armature ( used this on my Witchchan-Trapped in the Game Model —> didn’t fail)
- Baking the Animation, as shown in the video below (no more weird shifting)
Baking the Animation.mp4 - Google Drive
starts at 00:20 sec
If you don’t mind, I would suggest to join some of the tiny background cars together, because this would improve upload time and performance massively. Right now each car has their own set of animation, and sketchfab has to look at all of them (Another advantage of using armature). I also tested how the road would look with the decimate modifier and thought it was neat