Torus to SubD?

Rhino SubD
1

Hi…,

I am playing with subD.

A trimmed torus segment isn’t nicely converted to SubD, I get a complete SubD torus. Also a shrinked nurbs torus gets me a bad conversion.

Rhino_Torus_to_SubD_seg
Rhino_Torus_to_SubD_seg.jpg1250×879 180 KB

torus_to_subD.3dm (294.9 KB)

Any ideas?

Thanks

Michael
www.flexiCAD.com

2

Hi Michael,
A good way to make lightweight and precise SubDs is to interpolate a mesh with vertices on the NURBS surface.

SubDKnotVertexDirection
SubDKnotVertexDirection.PNG1110×719 118 KB

See attached TorusSegment.3dm (162.7 KB) It needs some experience to figure out how low you can go with the point count. The SubD-friendly-option which you’ll find in some commands is not yet there… :wink:

3 Likes
3

Hi Michael - The problem,I guess, will show up any time you have a subd ending ‘in space’ like that - SubDs have zero curvature at the open edges, so it can never match the arc shape there. It will take more points to make it all more arc-like but right at the edges this will fall apart.

-Pascal