Hey, everyone! Is there a way to remove one of trim edge while keep inner loops in C#？ UntrimSpecialEdge.gh (1.2 KB) [ScreenShot_2025-12-16_222325_398]

do you need this in a more complex scenario or for planar Surfaces only ?

in complex surface not planar, it’s easy to untrim the outer loops in Rhino, but i dont konw how to untrim in C#

my guess you have to rebuild the brep. As far as i searched, there is no “delete Edge, delete 2d Curve, delete loop” or similar functionality exposed to Rhinocommon less code and hazzle get the inner loops from the surface as 3d Curves get the underlaying surface and create a “isSurface” Brep Spl…

Hi @朱钟鸿 , There are no functions, in the Rhino SDK, to untrim Breps. I’ve logged the wish. Add Untrim function to Rhino SDK : RH-91107 https://discourse.mcneel.com/t/how-to-untrim-one-of-trim-edges-while-keep-inner-loops-in-c/213696 There are no functions in the Rhino SDK to help devel…

Thanks bro, extract and resplit is a way, but not efficient because split operation is too slow. Dale said that there are no functions in the Rhino SDK, This is my solution: 1.reconstruct the planar holes surface(easy and quickly) 2. remap it back to the complex surface Brep.CopyTrimCurves. And S…

This is my solution: 1.reconstruct the planar holes surface(easy and quickly) 2. remap it back to the complex surface Brep.CopyTrimCurves. And SampleCsFaceWithHole.cs seems to work on complex planes as well？There is another unbelievable solution: I extracted the outer loop of underlaying surface…

RebuildTrimmedSurface.gh (132.0 KB) it works but i dont konw why

RebuildTrimmedSurface.gh (132.0 KB) it works but i dont know why

How to untrim one of trim edges while keep inner loops in C#？

Rhino Developer

brian (Brian Gillespie) June 23, 2026, 9:13pm 10

RH-91107 is fixed in Rhino BETA

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How to untrim one of trim edges while keep inner loops in C#？

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