MoveFace and other tools/operations which shrink surfaces

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.)

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Now that I think about it… Rhino always pops up a warning that a change may “delete history”.

I think Rhino should also pop up a warning any time a change may “shrink surfaces”!

Hi Robert -
Could you post an example of where surfaces shrink when using the commands that you have listed?
-wim

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.

Without seeing an example and knowing that this does not happen in anything I try, I’d say it’s a bug, yes.
-wim

Direct editing also shrinks all surfaces of a polysurface.

DirectEditShrinksAllSrfs

DirectEditShrinksAllSrfs.3dm (40.1 KB)

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Thanks for that example, Steve -

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.
-wim

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Just noticed an example:

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)…

moveface

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Hej Robert -

I’ve added that example to the same issue.

I see that you were able to change the topic subject line to something completely different than it used to be…

As I said before, we have several items on the list for things that happen when direct editing polysurfaces.

As for the original topic of this thread, Joining, Booleans, or FilletEdge are something else and I still welcome examples of where those commands do the same.
-wim

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If you ever manage to ExtendSrf on a polysurface, I just noticed that this also immediately shrinks trimmed surfaces. :expressionless: