How to cut a plane in a shape of another planar mesh?

Question

I have a terrain-looking plane made with Geometry Nodes (gray in the image below) and I would like to cut out a "meadow" on it (yellow in the image below) to assign different materials to the two parts.

I've created the "meadow" mesh outside of Geometry Nodes by cutting a plane in the shape I like. From there, I've brought this mesh into the geometry nodes and extruded it to intersect with the "landscape". With the Mesh Boolean node I am able to select the "outside" part of the landscape, but can't find a way to select the part inside the "meadow" extrusion.

Any help is greatly appreciated!

https://blender.stackexchange.com/questions/50538/how-to-cut-an-object-along-a-curve/ https://blender.stackexchange.com/questions/77279/projection-geometry-example/77281#77281 — Duarte Farrajota Ramos, Oct 27 '22 at 21:48
@DuarteFarrajotaRamos Are you sure that this is a duplicate? The question was about [tag:geometry-nodes] (and would need more details to allow an answer). — quellenform, Oct 27 '22 at 21:57
Indeed, good catch, sorry about that. Missed the part that it was about geometry nodes — Duarte Farrajota Ramos, Oct 27 '22 at 22:27

score 1 · Answer 1 · answered Oct 28 '22 at 05:58

1

you can just use mesh boolean with intersect and difference:

answered Oct 28 '22 at 05:58

Chris

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score 1 · Accepted Answer · answered Oct 28 '22 at 11:25

If you want to get both the inner mesh and the outer mesh, and have the inner mesh follow the contour of the terrain, you would (unfortunately) have to use two Mesh Boolean nodes:

One node intersects with Difference the inner part from the outer, and the other node intersects the inner mesh with the terrain, so that a mesh is created that corresponds to the surface of the terrain.

But to also remove the side parts created by the extrusion, you would have to capture a boolean value in the geometry of the meadow mesh before this action, and use this selection afterwards to remove the excess faces.

_{(Blender 3.2+)}

How to cut a plane in a shape of another planar mesh?

2 Answers2