Flattening out and dissolving faces using geometry nodes.

I have an object that will be 3D printed and I was wondering if geometry nodes can flatten out and dissolve faces. I currently select the faces and use S-X-0. The goal is to model this completely in geometry nodes to make it procedural with the ability to change various parameters like the heights and size.

See animation below of what I do now. Can Geometry Nodes do this? img1

My current node setup can extrude but not flatten and dissolve faces. img2


1 Answer 1


You can flatten them with the Scale Elements node in Single Axis mode with Scale set to 0. By default, the pivot point for the operation is the median point of the selection, but you can choose a different vector through the Center socket:

enter image description here

Do note that while in this example the selection job was easy thanks to Extrude Mesh providing it, that wouldn't necessarily be the case every time—you'd have to come up with various other filtering techniques using input nodes like Index, Normal, and others... but still, it's doable.

What is not doable, yet, as far as I know, is dissolving edges. There is a Delete Geometry node, but it doesn't have a dissolving option. You could, theoretically, employ the Merge by Distance node along with some isolation and selection tricks, but in this case the best I could do was this (which is not even manifold since it can't properly merge with the rest due to lack of vertices on the long sides):

enter image description here

enter image description here

  • $\begingroup$ Thanks..I'll add it to as a request to see if they'll add it as an option in a future version of blender $\endgroup$
    – Rick T
    Commented Mar 27, 2022 at 0:45
  • 1
    $\begingroup$ @RickT just out of interest, why dissolve the edges? I can imagine ways for other cases, but in this case, it would seem to wreck the topology for no good reason? $\endgroup$
    – Robin Betts
    Commented Mar 27, 2022 at 8:10
  • $\begingroup$ @RobinBetts Sure, I wanted to work with a single face index to make it easier to find. I'm going to attach a procedural generated object based on the face index. Easier to find one index then to search through a bunch. But I'm starting to rethink it, as you say if it's worth wrecking the geometry. $\endgroup$
    – Rick T
    Commented Mar 27, 2022 at 9:35

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