Hi Michael,

I guess if history could remember the trims, joins and deletes that go into a Boolean operation and sort them out, untrim
could undo the effect of a Boolean on a particular surface without acting on other surfaces that were involved in the Boolean.

This comes into play when a client sends me a .3dm file to mill that isn't built correctly and asks for my assistance in repairing/rebuilding it.

Essentially, after untrimming a surface, I usually delete it and use the edge curves of the rest of the model to rebuild the section, but at least it can save me from the impossible task of pick out a lot of little surfaces to delete while making sure they all belonged to the surface in question and not something else. For instance, when a surface has been pierced and cut up in many places such as on a polysurface of a ring with multiple little stone settings or other small embellishments added or subtracted. The stone settings and other parts can also be untrimmed and restored to their original state, so I can fix something pretty quickly, without having access to, or even needing to deal with the original construction curves (which probably caused the problem in the first place).

Thanks,

Jesse