Convert Untrimmed Surface to a Mesh with Edges Matching the Isocurves

I’m currently working on a 3D modeling project and facing a bit of a challenge. I have an untrimmed surface in my model, and I need to convert it into a mesh. However, the crucial part of this task is ensuring that the edges of the mesh are an exact match to the isocurves on the surface (as in that the 2 “grids” overlap).

The isocurves are all polylines. I’ve tried a few methods, but none seem to give me the precision I require. Sometimes, the MeshBrep node gives the correct result, but as in the case of the attached file, there is a mismatch. I cannot find a logic why this happening

Any advice or suggestions would be greatly appreciated!

Thank you in advance for your help! (17.3 KB)

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One thing you can do is project the surface to the XY plane, mesh it and project the vertices back to the surface. (18.4 KB)


I was about to show you these two methods:

HOWEVER, what @martinsiegrist did is what I originally intended to do via surfacepoints but it didn’t work - I know why now :wink:


The Q input is relevant.


Hi @martinsiegrist , @corellaman thank you both for having a look. Never used Mesh UV and SurfacePoints, so always nice to use new nodes

The first method proposed by Martin is a perfect fit, but quite slow. My final srf has 10.000+ isocurves, so that’s a crash waiting to happen

The second method you suggested is off when viewed in Perspective. Or am i missing something

The fastest and “close to accurate” seems to be Delaunay mesh. Although there are still some mesh triangles in there.

let me attach the proposed methods in gh file.

Looking forward to other suggestions to speed things up and get a ‘perfect fit’ (33.2 KB)

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@Petras_Vestartas made a nice and fast node “QuadDivide” that gives a clean mesh. may come in hand if someone needs something similar. (63.2 KB)