Split a Delaunay Mesh

I am trying to split a surface using curves but the surface a very large and made from around 7 million polygons so the split command keep failing. I created a mesh with the delaunay component using points from DTM data (image below).

The curves I am using are all booleaned curves (image below)

1- The main problem is that the split command doesn’t work on the large mesh
2- The command does work on a small section of the mesh but it leaves open faces

Is there a method to split the mesh with grasshopper and not create a jiggered edge, so that when the split is done the edges follow the path of the curve, like in a ploysurface? All help and advise is very mush appreciated.

this mesh is vast and the curves are very complex.

Rhino’s capabilities in this regard are,… limited.

Had these problems myself.

I remember, that somehow using actual extrusions instead of using the curve directly works better.

-MeshSplit command

Also I think you could try to split your curves in smaller parts and do it bit by bit.

*if you can upload the file, it would be easier to help

Change document unit to cm might help.

Thank you for the advise, unfortunately the file size is too large to upload, I saw this method (How do you trim or split a delaunay mesh) and wondered if I could use this?

@dk2079 I tried your method of extruding the curves and then using the extrusion to do a split but the application doesn’t get past 74%. I also tried to match the polygon count of both meshes and the progress wheel just keeps spinning.

A solution could be to recreate the mesh with again delaunay after you added intersection points.

Get the edge lines of your initial mesh. (E)
Project those line segments to the same plane of your curves.
Do all the intersections.
Use interesction parameters on original edge curves (E) to retrieve the points.
Re-create the delaunay mesh.

Resulting mesh will have a topology that already have the “cuts” you need.
Then you can simply cull faces using curve to find face centers containments.