We use a similar offset 'buffer' for infrastructure interference or to see if works between one subtrade will conflict with another subtrade, but this is 2d only.
The need for a radial offset buffer really complicates the requirement, especially the hemisphere/bubble endcaps or 1/4 sphere 'corner' for a box solid. Would a union of rectangular bounding box work in this situation? (maybe moot if you get to that point)
To busy to code today, but procedure might be:
- Select a subentity 3dsolid (this is the hard part, I don't work with 3D enough to know if you can decrypt a solid into original entities. Boy easy if you have the individual items)
- Get entity ucs. This would define the principle axis. However, no good if you have an entity with a lot of twists and turns
- Get bounding box coordinates of entity (see Marko Ribar's procedure here
https://www.theswamp.org/index.php?topic=51384.msg565073#msg565073 )
- Nudge coordinates away from each other, with respect to entity UCS
- Make '3dbox' solid in entity UCS
Then reset to WCS and union all the 3d boxes.