Convert SubD "Control Point Net" to Mesh Faces without Smoothing?

Is it possible to convert the shaded “control point net” for a SubD model into a mesh model without smoothing? If a SubD model is converted to a mesh (using the “Mesh” command), smoothing seem to be applied with even the lowest smoothing level. Is there a method for converting the SubD geometry to mesh geometry in its unsmoothed form?

You can use the command “ExtractControlPolygon” to get an actual mesh.
Then you can see it “sharp” by enabling Flat shade mode or you can Unweld that mesh.
(but note that unweld actually increase vertex count of the mesh)

Perfect; thank you, Riccardo!

It would be useful to be able to save a SubD model with adjustable smoothing onward from the “box model”. For instance, Smoothing = 0 (would be box mode with no smoothing) and then smoothing could be added in increments. Smoothing =1 or 2 or 3 etc.

Hello - why?


SubD boxmodeling is seriously fun and would like to see more features developed around it.

Hello - no doubt, but I’m curious what advantage you’d get from the feature you describe, exactly?



A command that exports a copy of the base Sub D model at multiple resolutions easily would be convenient since the same model may be used for different purposes: low resolution for animating in a program like Maya; high resolution for 3D printing, etc.

My understanding is Rhino directly creates the smooth version of the SubD model. Rhino does not create the smooth version through repeatedly dividing the mesh as some other software does. Rhino automatically meshes the smooth version for display/rendering purposes. Users can use QuadRemesh t ocreate a mesh version of a smooth SubD for export with influence over the mesh composition.

Hi @wm_c
You can use Weaverbird’s Catmull-Clark Subdivision in Grasshopper to do this very easily. Just input the extracted mesh and plug it into the WB component.

HTH, Jakob


SubD modeling is so speedy ive been using it for initial design concept iteration. I would like to capture some of these quickie concepts in various smoothness states.

The Rhino SubD surface is not a polygonal mesh with subdivision levels like in a polygonal modeler. Instead it’s a surface and the smooth display render mesh of it is called the limit surface which corresponds to a high level of subdivision (e.g. 5 or 6). The Tab key shows you what looks like level 0 but it’s really just a shaded version of the control point display (F10). You can use the Mesh command to create subdivisions of the control polygon using the SubD meshing parameters slider but those objects will be meshes not SubDs and if you create a SubD from them afterwards, in any density higher than the control polygon, you’ll end up with more SubD faces than you had originally. However, the SubD meshing parameters slider can also be found in the document’s render mesh settings or in an object’s custom render mesh setting and this will impact the Raytraced display mode or when you Render the model.

So if you want to capture smooth levels visually, the custom render mesh settings can help but if you create meshes of those levels above the control polygon, they’ll make a denser SubD if converted back.