Hi Harry, it's more likely to be a problem with the model geometry than a lack of computer power.

Part of the process of a shell operation is generating an offset surface.

That's kind of like tracing along the surface with a pole and generating a surface at the other end of the pole. If you have any areas where the surface folds over top of itself or has a lot of "high frequency" bumps in a small area those get magnified at the other end of the pole.

The surface probably needs to be generally higher quality, smoother and simpler for an offset of it to not explode into tremendous complexity.

This is all kind of a guess though, it's hard to know for sure without being able to examine the model. If you can please post the .3dm model file with the object you are trying to shell that would help to give more specific advice. You can e-mail it to me at moi@moi3d.com if you don't want to share it publicly.

- Michael