Can I move just some of the verts on a mesh?

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I would say "terrain," but I don't think I want to use Unity's built-in Terrains for this. What I am trying to avoid is setting every single vertex's position every single frame when there are only a handful of them that are actually being moved. I think being able to do this is make-or-break for the feasibility of a new game concept I'm kicking around.

I think I should have an array (dictionary) of vertex numbers vs world space x-z coords. Then another of vertex numbers vs an array of all the numbers of that vertex's closest neighbors. (Which is probably harder to calculate than it is to say.) Am I on the right track though?

The procedural examples all iterate through every vertex in a temporary array and then set the mesh's vertex positions (or colors) all at once. Is there some reason why you "have to" do it like that?

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Answer by Eric5h5 · Oct 18, 2012 at 04:45 PM

You must update every vertex in a mesh even if you only are changing a few. However, you don't need a temporary array. You can use a permanent Vector3 array for the vertices, and only change the relevant entries, but doing "mesh.vertices = myVertices" copies the entire array to the mesh, and is the only way of updating meshes.

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Kiloblargh · Oct 18, 2012 at 05:06 PM 0

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Ok; that's what I was thinking. I guess I can test it myself, but is doing that every frame a big framerate hit and is "mesh.vertices = myVertices" expensive in direct proportion to the number of vertices being copied? (If so might just say "#$@*% it, I'm going voxels.")

Eric5h5 · Oct 18, 2012 at 09:34 PM 0

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is doing that every frame a big framerate hit

Depends on the size and number of the meshes, and how fast the hardware is.

is "mesh.vertices = myVertices" expensive in direct proportion to the number of vertices being copied?

Yes.

Can I move just some of the verts on a mesh?

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