Surfaces' isocurves get "stretched" when modifying Polysurfaces

When modifying PolySrfs with a SolidPtOn command or by dragging their edges I notice that sometimes their surfaces’ isocurves get “deformed” - please see the images below. Their boundaries stay the same, but the surface “definition” seems to get “stretched”.

Is it documented anywhere to understand what causes it or how to avoid this behavior? Or perhaps is there a way to repair them after that happens?

Hi Daniel -
Generally, I’d be reluctant to solid-editing objects unless they are very simple.
In this case, you’d have to post your 3dm geometry but, depending on which edge is getting moved, that might work fine?


1 Like

thank you Wim and sorry for the late reply - it took me a while before I came across this issue again. Please see the sample 3dm files below together with a visual explanation of the problem:

If you are aware of any way to prevent this behavior or “easily” repair it afterwards that would be really useful.

2.3dm (1.5 MB)

4.3dm (1.5 MB)

Hi Daniel - Maybe Wim will have better luck reproducing than I did but, getting back as best I can to the pre-edited object it all seems OK now. I replaced the two wiggly faces in that object and moved the face you indicated as well as others - seems to work-

So there may be something in the original object’s faces, or edges, is my guess - that we should see - I’d say if you see this again, Undo, and then send the object with an indication of what face to move, just as you have here.


1 Like

Great, thank you, if it crops out again I’ll send it.

maybe some stuff is not precise ?

maybe a mixture between workaround and analyse:
subselect and delete the (expected to be planar) crazy-iso curve-surfaces.
(do it one after another)
should close those planar openings again.
if cap is not able to close, the surface is no longer planar. - something went wrong with the SolidPt edit…

sorry for the late reply @Tom_P, you are right that most likely this was caused by some imprecision in the modelling. When exporting them to sketchup now it causes some faces to be triangualated and some not (image below).

It makes me wonder if there is some way to automatically realign the vertices to rectify these micro imperfections. Then again it may require the model to have some constraints, otherwise connected segments might become distrorted.