Hi Nick, I also did a tune-up for mirror so that with non-solid surfaces, the surface normal direction will stay consistent with the original when mirroring, instead of the normals getting flipped.

Kind of an overhaul of normals handling for non-solids in general. I think it should solve many of these problems but there are a fair number of changes so please be on the lookout for any bugs in this area for the next beta.

- Michael