SubD - get edge to conform

Rhino SubD
1

  1. How do I get an end edge of a subd surface to conform to a defined shape. For example the outer edge of my subd surface is a slightly distorted ellipse. I would like it to conform to a perfect ellipse.

  2. Similar question: I have a helix that I want to conform to the surface of a cone. How to do this? (I realize I can taper a helix but am simplifying my question.)

Thanks you in advance, Mike

2

Hi Mike - in general, SubD is not as suited to making exact circles, ellipses etc. as Nurbs.

-Pascal

3

You can use the Align command > To Curve option to align control points of the SubD to an ellipse curve. If you have at least 8 points it’ll be pretty close but as Pascal mentioned not as precise as NURBS.

For the Helix question, Pull or Project may work for you but it depends on how far the helical curve is from the surface.

4

Thanks Pascal. Lets assume convert from subd to nurbs before this operation.

5

Hi Brian - how to use project or pull in a radial direction? it is very close.

6

Hi Mike - turn on the subD points, seolect the edge ones and Align >ToCurve, using the circle as the target

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-Pascal

7

Post a 3dm file to show the specific objects you’re working with. You can use the Export command to save out only the selected objects too. Project uses the Cplane normal and Pull uses surface normals.

9

Sure, email tech@mcneel.com with a comment and the file or use www.rhino3d.com/upload if it’s too big to email. Say for BrianJ in the comment and I’ll see it.