This is an old post, but it’s the first thing that comes up when searching and I worked on a solution for this that I wanted to share:
This will scale/expand ring shaped objects including flat rings, toruses, or any other 3d rings while retaining their original width. Simply change the X and Y scale in the object transform.
Restrictions:
- The ring mesh must be horizontal (just the original import, you can rotate the object atter)
- The pivot point must be centered.
- This assumes your X and Y scaling match and Z scale is static
- Any collision on the mesh will not match the shape when scaled.