# How to create a Sierpinski Dodecahedron fractal

I can create a Menger sponge fractal using geometry nodes.

See Blender file below:

Now I'm trying to create a Sierpinski Dodecahedron

I tried to replace the cube node with a Dodecahedron created as an object but that didn't work

The goal is to create the Sierpinski Dodecahedron fractal that can be sliced into several sections and 3D printed out.

• Have been discussing this with @lemon just recently .. have got this far.. but running into floating-point errors in the dodecahedral case. Got to get the maths right for the scaling factor. And I know, on my machine, if I go one level further I will crash Nov 20, 2021 at 20:13

with this node setup:

you get this:

one more instance level:

• Great stuff! How did you determine your scale factor? I wound up with accumulating deviations.. (Mind you, the resolution will surely be greater than any printer's, anyway...) Nov 21, 2021 at 8:17
• Thank you!!!!! I just read the wiki article 😅 Nov 21, 2021 at 8:31
• One more level and my computer still worked but Blender crashed everytime…😢 Nov 21, 2021 at 8:32
• :) I thought I'd read the right wiki article.. but apparently not... link? I think we still both have a problem... coincident (duplicate) instances ?? .. you could maybe squeeze another level out.. Nov 21, 2021 at 8:53
• that gives the scale factor for instances in the corners: 1/(2+phi) I've still got to work out the factor for instances on the corners? I'll get to it.. my neurons aren't firing atm. Need coffee. Nov 21, 2021 at 10:05

This setup works for every fractal. The current scale factor (the Value and its Math node) is set to scale dodecahedrons, but it can be adjusted for other primitives (usually you would change the Power to a Multiply).

To anyone who wants to render this, I recommend 3.0.1, because more recent versions cause artifacts with overlapping geometry (it's a known regression).