I made a height map based on a displacement, with a very high vertex count. However, some parts of the map are flat because the terrain actually... is flat. I have now 1 million vertices, of which at least 80% are quite useless.

So: I would like to mass-dissolve vertices that are: - adjacent to each other - same height ...so that the flat parts of the terrain would become simplified, to reduce unnecessary vertices (and thus file size and CPU effort etc) Screenshot edit mode

I do want to keep the steep hills and canyons with a lot of detail of course, as you can see on the lower half of the image. It's just the flat parts I want simplified.

Is there a way to do this without doing it manually? Because that would take ages.

PS: I tried "limited dissolve" but that kills the app.

Thanks in advance.


You can select one top face, then shiftG > Select Similar > Normal, then ctrlE > Un-Subivide.

enter image description here

Also, you have the Decimate modifier / Planar mode that will unsubdivide all the faces on the same normal orientation, or according to a certain angle threshold, it will allow you to preserve all the details:

enter image description here

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  • $\begingroup$ The modifier crashes my computer :-) But that seems powerful. So I tried the first option, which is "ok", but would still take some work... But true, less work! $\endgroup$ – Fré Jun 10 at 10:21
  • $\begingroup$ Ooh too bad, maybe try with a previous version of Blender? But it might be because it's too much to calculate... $\endgroup$ – moonboots Jun 10 at 10:22
  • $\begingroup$ When I have a very slight slope, It actually looks like very long flat steps. Is there a way to have that simplified to "actually a continuous slope" in stead of planes going down one by one? $\endgroup$ – Fré Jun 10 at 10:24
  • $\begingroup$ I think I'm gonna lasso those parts and un-subdivide.... that kind of does the trick $\endgroup$ – Fré Jun 10 at 10:26

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