Reduce Mesh (cull overlapping vertices) while keeping Vertex Colors?

[crz_06]

Hi everyone,

My aim is to reduce a large mesh that is made up of an array of joined pyramids, totalling over 4.5 million vertices. I can reduce it to ~750k, but in doing so I loose the vertex colors. So the question is how to cull/weld these overlapping vertices (or rebuild the mesh) while keeping the mesh vertex colors intact.

So far, I’ve tried several approaches, but I keep hitting snags:

• Kangaroo2 (Clean & Combine), MeshEdit (Cull Unused Vertices) and Pufferfish (Rebuild Mesh) and Nautilus (Weld the Vertices of a Mesh) - Successfully reduce vertices, but they strip the vertex colors from the output mesh.
• WeaverBird (Join Meshes and Weld) - Reduces the vertices, and keeps the vertex colors but messes them up when vertices are welded.

I’ve attached a small portion of the mesh as a GH file to illustrate the setup. Has anyone had success with similar projects or know a method/tool that can merge overlapping vertices while preserving vertex colors?
clean_mesh_keep_colors.gh (92.3 KB)

Any advice or tool recommendations would be greatly appreciated!
I don’t need grasshopper for this, a rhino command is fine, it’s just that i am more familiar with it gh than plain Rhino

PS: I cannot to back to the source file to see if I can somehow rebuild it differently.

Thanks!

[laurent_delrieu]

Hello
there was some discussions on face Coloring but I didn’t test that. Perhaps @AndersDeleuran could help on this subject. Keeping vertex color seems to be a bad idea here because color will be mixed. but its is doable.

Mesh Face Coloring

What is the most efficient approach to mesh face coloring for a large mesh (say 50,000 faces or more)? Each face will be painted a solid color based on user-defined information. The approaches I have considered so far include: a. Display conduit in which I draw each face as a polygon with a specific color (first attempts at this seem to be very slow). b. Add redundant vertices to the mesh so that each face has its own set of 3 or 4 vertices and set vertex colors (seems less than ideal). c. Br…

Color Mesh Faces (No Bleeding) - Best Practice?

Hi @dale, apologies for reviving this topic again after a few years. But I just came across these two issues described above again, and they kinda keeps resurfacing for me it seems: For the first issue, perhaps there is already something in RhinoCommon I’ve missed? Basically something like the opposite of Vertices.CombineIdentical I suppose. Maybe you have some ideas as well @DanielPiker, all meshy and such. If anyone else have some new insights on how to best/most performant (with RhinoCommo…

What I can propose is for you to transform the color to a bitmap texture.

In order to do that your initial mesh must have texture coordinates.
Command: _ApplyPlanarMapping

Here the script 6s for 1024x1024 pixels texture, 25 s for 2048
clean_mesh_keep_colors_LD.gh (97.8 KB)

[crz_06]

Thanks for liking into my file, Laurent. Much appreciated

I missed that topic you referenced, interesting read, had no idea that facet colring could be done.

[inno]

this will give you, for each vertex in the reduced mesh, the List of colors that were applied to those vertexes in the original -complex- mesh:

clean_mesh_keep_colors_inno.gh (78.5 KB)

but once you see vertexes in the very same given location originally had like 8 different colors applied: which color you want to keep?

[AndersDeleuran]

@crz_06

My aim is to reduce a large mesh that is made up of an array of joined pyramids, totalling over 4.5 million vertices. I can reduce it to ~750k, but in doing so I loose the vertex colors. So the question is how to cull/weld these overlapping vertices (or rebuild the mesh) while keeping the mesh vertex colors intact.

That’s not possible, as far as I know. One must unweld all vertices in order to color faces without them “bleeding” into each other (which is now a lot faster at least, but also your mesh is already unwelded). This was partly the issue explored in the topic @laurent_delrieu linked to above, maybe going through that can help clear up some misunderstandings. Also, before checking your mesh I quickly slapped this together from your old topic and this one, demonstrating methods discussed:

241031_MakeAncColorPyramidMeshes_00.gh (646.4 KB)

[AndersDeleuran]

Here’s a quick Rhino 8 version. The threading seems to work quite a bit faster, or maybe that’s the NETCore performance boost. And the mesh face coloring is now about three times faster on my system… very niiiiice:

241031_MakeAnDColorPyramidMeshes_V8_00.gh (661.7 KB)