GH-Only Catmull-Clark Subdivision

As an exercise, I decided to try to implement the Catmull-Clark subdivision algorithm in Grasshopper alone. This means no scripts, and no 3rd-party components (such as weaverbird). This is not designed to be a utility - by all means, if you have to subdivide a mesh in this way, just use Weaverbird. I am always interested in the way traditional coding approaches translate into a non-textual language like Grasshopper, and this was a fun way to push a bit at GH's data management to achieve comparable results to scripting approaches.
The algorithm as implemented can handle closed meshes with quad faces only. I will attempt a version that can handle tri-faces eventually.
I based my approach on the pseudocode available at Rosetta Code.

DOWNLOAD HERE: GH_Catmull_Clark.gh

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Comment by Morgan Rohla on February 3, 2021 at 5:44am: Catmull-Clark subdivision is really hard for me to draw on Autocad because there are many cuts that we have to make to make it perfect. All the students read Study Moose reviews before they hire an online writer to complete their work on time. I believe after reading your discussion about Catmull-Clark I will be able to make it on my own software on time.

Comment by June-Hao Hou on March 15, 2012 at 6:32pm: Great exercise! Bravo!

Comment by Ángel Linares on June 28, 2011 at 3:12am: Really nice exercise :) tri_vertex and quad faces compatible definition could be a little tricky to code... I'll love to see.

Comment by Archieboy on June 26, 2011 at 2:17am: Very nice! I want to know if there is anyway to do the reversed way: from a very high density mesh(like the red one in your picture) to a more polygon mesh (like the blue one)?