So the wheels have a boolean modifier on them and in the dropdown menu it says difference, and it looks correct in blender. but when i upload to sketchfab, the appearance it takes in is what it would look like if i had selected "intersect" instead of difference. So I ended up just changing it to intersect. It looks wrong in blender but it looks good in sketchfab. Just curious if anyone knows why. Is there something I may have done that is causing the two to operate inconsistently?