Adding selection input to Subdivide Mesh geometry node #116485

Eugene-Kuznetsov · 2023-12-23T07:57:26+01:00

Eugene-Kuznetsov commented

2023-12-23 07:57:26 +01:00

It is sometimes useful to subdivide some part of a mesh using Geometry Nodes (perhaps to increase detail level in the area that is to be modified, without incurring performance penalties due to global subdivision).

At present, there's no good way to do it. The obvious approach is to "separate geometry" followed by "join geometry" and "merge by distance", but it does not work as intended, because it leaves zero-area holes along the weld, which manifest as shading discontinuities. It takes a lot of work to fix the gaps (https://blender.stackexchange.com/questions/274918/how-to-subdivide-a-selection-of-faces-in-geometry-nodes) and even that does not work 100% correctly.

This PR adds a Selection input to the Subdivide Mesh geometry node. I had to switch to a different subdivision algorithm, because I can't see any way of passing selection data to the original algorithm, and I'm not sure if I got all the allocation and deallocation logic correctly. It does seem to work, though.

Original:

With the new Subdivide Mesh node:

It is sometimes useful to subdivide some part of a mesh using Geometry Nodes (perhaps to increase detail level in the area that is to be modified, without incurring performance penalties due to global subdivision). At present, there's no good way to do it. The obvious approach is to "separate geometry" followed by "join geometry" and "merge by distance", but it does not work as intended, because it leaves zero-area holes along the weld, which manifest as shading discontinuities. It takes a lot of work to fix the gaps (https://blender.stackexchange.com/questions/274918/how-to-subdivide-a-selection-of-faces-in-geometry-nodes) and even that does not work 100% correctly. This PR adds a Selection input to the Subdivide Mesh geometry node. I had to switch to a different subdivision algorithm, because I can't see any way of passing selection data to the original algorithm, and I'm not sure if I got all the allocation and deallocation logic correctly. It does seem to work, though. Original: ![image](/attachments/a4aa0ef8-3678-474b-98e8-b98a6c7c12ca) With the new Subdivide Mesh node: ![image](/attachments/5cf00c20-f5de-44ec-9896-fe25708c0167)

image.png

2.4 MiB

image.png

2.5 MiB

❤️ 3 🎉 2

Eugene-Kuznetsov changed title from ~~WIP Adding selection input to Subdivide Mesh geometry node~~ to WIP: Adding selection input to Subdivide Mesh geometry node

2023-12-23 07:57:55 +01:00

Iliya Katushenock commented

2023-12-23 09:02:41 +01:00

The main problems here:

Using bmesh.
Selecting not polygons, but edges.
Not the subdivide level, but the selection of subdivide.

The main problems here: - Using bmesh. - Selecting not polygons, but edges. - Not the subdivide level, but the selection of subdivide.

Iliya Katushenock added this to the Nodes & Physics project 2023-12-23 09:02:52 +01:00

Iliya Katushenock added the

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Adding selection input to Subdivide Mesh geometry node #116485

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