# is it possible to detect edges/curvature in blender geometry nodes?

Working on a non-destructive asset (roofing tiles) and I'm trying to use vertex colors to define edges (red vertex color) and curvature (green vertex color)

There's meant to be an edge detect node in geometry nodes, but I cant seem to find it. The example below is done by handpainting in vertex colormode. However trying to find a more efficient way of doing it.

Similar to how the AO node works in the shader nodes (however that becomes prohibitive after a while since there's no quick way to bake down the shader without baking out afaik)

So the question is:

Is there a good way of generating vertex colors (similar to example) based on the geometry in geometry nodes?

• As an idea of how to approach this, I might consider sampling the nearest-face-interpolated normals of the mesh, at infinitesimal, object-space offsets in the plane of the normal, in the plus or minus direction of the normal, via a raycast node, and measuring the difference in normals. If it doesn't hit, that also tells you there's a mesh boundary. This has the property-- advantage or disadvantage-- of ignoring ripped edges. May 5, 2022 at 14:32

## 1 Answer

you can use a node setup like this to get this effect:

if you have less geometry, the effect will look like this:

• Thanks! that's along the lines what I was looking for. I have one problem though, I cant for the life of me find where the edge neighbors live. On the blender wiki it says nothing wheter it's nested under a math/vector or similar. Searching for it gives no results really May 9, 2022 at 13:58
• If my answer helped you, please click on the checkmark left to my answer. If you have another question, please open another question so that everybody can learn from it. Answers or questions in comments doesn’t help the community. Thanks. May 9, 2022 at 14:00