Ended up here again… this time, I haven’t used Offset… but I have used Join, Booleans and FilletEdge.
Of course, I later discovered that my fillet was “wrong” and since there’s no “delete fillet” in Rhino I had to remove it manually… only to discover that the surfaces had been shrunk for some reason… luckily I had backup surfaces but not a happy camper right now.
(EDIT: I thought I could edit the title of this post to become a more general “what tools in Rhino shrinks surfaces without telling you” question, but I’m not allowed to change it.)
Well, as in the previous thread, it took me a while to discover what the actual culprit was, and this is a similar situation (didn’t discover the issue until days later). When I find out what causes it, I’ll post. Right now, I’m cleaning up the damage.
In the meantime, if you want, I’d suggest naming this thread “Rhino shrinking surfaces without warning”, because that’s the core of the issue to me… (unless that’s always a bug, because I can’t actually reproduce it anymore using offset solid=yes)… I think it’s just as serious as deleting history without warning would be.
RH-70105 ON_TransformBrepComponents: Move edge shrinks surfaces
We have several items on the list for things that happen when direct editing polysurfaces. For the time being, I wouldn’t expect that to “just work” on anything but very simple cases.
Joining, Booleans, or FilletEdge are something else and I still welcome examples of where those commands do the same.
MoveFace shrinks faces not even affected by the move!
Overall, MoveFace would benefit greatly from an option that either preserves edges (which it seems to do today, which I don’t like) or preserves faces (in other words, doesn’t rotate faces like in the example below)…