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Using geometry nodes - How can we implement Catmull-Clark and Doo-Sabin Doo-Sabin subd. algorithms while exposing their parameters using geometry nodes.

I've been looking for coding examples on Michael Hansmeyer "Subdivided Columns" or something like it. I want to experiment and 3D print some small test models.

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I can find data on simple fractals

Getting the total length of all edges using geometry nodes and Fractals in Blender?

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But nothing on Michael Hansmeyer "Subdivided Columns" which was done in 2009-2010. Any thoughts in recreating something like this?

Background:

His Ted talk https://www.ted.com/speakers/michael_hansmeyer

A paper describing it.

http://papers.cumincad.org/cgi-bin/works/paper/ecaade2010_192

Website:

https://www.michael-hansmeyer.com/subdivided-columns

Update: As mentioned by Robin Betts I'm trying to re-frame the question.

Rick T
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  • Since you've provided no information on who 'Michael Hansmeyer' is or any links to him, how are we expected to answer that question? – John Eason Feb 10 '23 at 11:18
  • @JohnEason ok I added a link to his Ted Talk along with his paper. – Rick T Feb 10 '23 at 11:29
  • I don't know what you are expecting from us... should we now work our way through all the Ted talk and paper, find formulas for fractals and then figure out how to implement this in Geometry Nodes? Fractals are quite complex, you know - not trivial. This site is not for giving elaborate tutorials. Try this one by Bad Normals, here he is creating a fractal in GN: Blender is getting CRAZY! – Gordon Brinkmann Feb 10 '23 at 14:07
  • @GordonBrinkmann JohnEason asked for it so I posted it. I was just putting it out there. I'm always overjoyed any of my "crazy" questions get answered or get a response no matter what it is. It gives me different points of views I wouldn't have gotten otherwise. – Rick T Feb 10 '23 at 14:15
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    For those not prepared to go through the refs, these objects seem to be made by recursive subd, using atypical, and varying, parameters to Catmull-Clark and Doo-Sabin algorithms. Rick T .. maybe a better question for BSE is: 'Can you implement these subd. algorithms, exposing their parameters?' I like the project, but think it has to be reframed to be answerable here, BTW, these objects are hopelessly pathologcal, from a 3D printing POV. – Robin Betts Feb 10 '23 at 18:24
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    Personally, I hate to lose this question, but I think it has to be reframed for BSE. Try something like my suggestion above, so it's a definite question, susceptible to a definite set of answers. ( Like this, but you want to screw with the lengths, etc. ) . You can still link to the refs to show your motives. At the moment, this Q would be fine on a chat-forum, but not in a Stack Exchange archive. – Robin Betts Feb 10 '23 at 18:37
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    @RobinBetts I gave it a shot. It really comes from some emails / video from Dr Cohen he said you just have to try it. "In general, the fractal parts produce 'fractal loading' and makes the antenna smaller for a given frequency of use. Practical shrinkage of 2-4 times are realizable for a given performance level. Multiband behavior is manifest at non-harmonic frequencies" https://www.fractenna.com/our/antennatech.html . He's 3D printing them now so I just wanted to try something like it but with a little twist. – Rick T Feb 11 '23 at 05:52

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