again a Question related to Math & Geometry Node. I ´m still working on Algebraic Surface in Blender Geometry Nodes. Meanwhile the Integration of parametric equations wiht x,y,z, in Geometry Nodes works fine, but i still struggle with some fine details. The way to create 3D Objects in Geometry Nodes with the help of the Volume Cube (thx to @Markus von Broady) is a cool way for almost all kind of formula. (see; "implicit equation in blender?" Search an import way for implicit equation in blender?)

But to get the Workflow perfect i would like to cut the "Volume Cube" on the Outer Faces inside the Node-tree. I know it is easy to aply the Geometry Nodes and cut it later, but i hope there is a way to "clean" it with the help of a Node? As you see in the Picture, or in the Blend File;

VER1 is how it should look (i cuttet it afterwards) VER2 how it looks without cutting the outer Faces. Does someone of you know how to realize this in GN? Thanks for all ideas :)

Version one & two


1 Answer 1


one way is to cut it off via compare node with x,y,z coordinate:

enter image description here


enter image description here

  • $\begingroup$ Hi @Chris, wow, very simple and smart - works perfect. Great, thx! (PS: I don´t see a function or effect in the "lenght vector node", it right?) Saved my day 😀 $\endgroup$
    – smice
    Commented Sep 28, 2023 at 15:30
  • 1
    $\begingroup$ if my answer helped you, please click on the checkmark left of my answer. thx. the length node was my first idea. it kind of works, but then the cutout will be round/spherical. Don't know whether you wanted that ;) $\endgroup$
    – Chris
    Commented Sep 28, 2023 at 16:52

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