Fun with RhinoPolyhedra and SubD, and the need for mesh nGon Support in GH2

A while back I started playing with converting various RhinoPolyhedra meshes to SubDs, as a way of finding interesting geometry, and a way of creating nodes for pipe blends.

I made a simple definition that makes it easy to explore all the ways these polyhedra look when converted to SubD. Here it is, maybe you’ll find it fun: Polyhedra to (52.9 KB)

One thing that’s somewhat frustrating about this is that grasshopper’s native mesh components and many plug-in mesh components don’t play well with nGon faces. If there were more subD components, this would be less of a problem, but for now, mesh-based workarounds seem to be all we’ve got. The above definition is only possible with a python script that calls _addNgonsToMesh, and that, in turn, only works with planar ngons.


  1. Are there any plugins available that will do basic manipulation of nGon meshes without breaking them into triangles? Mesh joining? Welding? Creasing?
  2. Are nGon meshes inherently a problem in Rhino, and if so, will we see any change to that in v7?
  3. Are there more SubD components on the way anytime soon? If not, what resources should I look to to learn some basic python so I can write short scripts in the python component to call whatever subD commands are currently exposed in Rhinocommon?

Some examples from the definition posted above:
Some of the self-intersecting polyhedra create plant-like results in SubD:

Some polyhedra with non-convex faces end up creating weaves as SubDs:

Any Polyhedron with only triangle and/or quad faces will play well with Weaverbird, and unlike when we use Weaverbird’s catmull clark smoothing, with SubD we can convert to nurbs for truly smooth curved surfaces:

Many of the toroidal polyhedra produce simple, almost classic modern forms when converted to SubD:

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Fun… :ok_hand:

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Hi Max -

If you expect answers to these questions, I would recommend to make a new post for each of these with concise and clear information of what is wrong or what you are trying to achieve.

As for this one, no, probably not. They will likely have to wait until Grasshopper 2 becomes available for testing at some point in the future.