SubDThickenCurve - Thoughts

Hi, Some SubDThickenCurve thoughts:

  1. SubDThickenCurve would be more useful if the points where curves connect end up roughly in the center of the SubD pipe. Currently, curves that touch at acute angles end up outside the pipe. Additionally, other connection points may or may not end up residing inside the SubD with a seemingly arbitrary proximity to the SubD wall. Right now, if I want this highlighted point (first image shown below) to be roughly at the center, I have to move vertexes and just eyeball it…one-by-one. Maybe there needs to be a interpolate option?

  2. Why can’t we call it SubDPipe?

  3. I would love to see history enabled for this command.

  4. Is it possible to specify the number of SubD faces/edge loops between connection points when generating a SubD pipe? (See second image)

SubDThickenCurve_Issue.3dm (133.7 KB)


These are excellent wishes. I think in general the sub d cage is wrong it should be displayed inside the object and grow not shrink, that way curves that construct the cage will lie on the cage currently the cage is always displayed as larger than the final smooth sub d. I’ll post some examples.
I second Ryan’s requests. Also to have cap options, history enable and support for lines as currently lines degree 1 are not being sub d thickened I have to rebuild lines to degree 3 which is not the case with curve piping.


Cap options would be handy, too.

Thanks @ryan.rhino.odom and @3dsynergy, these are some good suggestions.
Capping options and setting number of edge loops along struts are definitely going in the next version.

Regarding the rounding at sharp vertices sometimes leaving the input lines outside the surface-
Currently the input curves end up in the center of the control cage

This does indeed mean that for sharp angles the input curves might not stay inside the resulting SubD

One approach I’m considering that could help when you want to avoid this is to have an option to create ‘elbow patches’ at sharp corners like these

It is also changing in the next version so that the input radius controls the radius of the subD itself, rather than of the cage.

I think the general question of whether SubD objects could interpolate the points of their cages is a larger one, not limited to this command, and deserves its own thread.


Hi Daniel,

Very nice that will be quite welcome especially the cap option for architectural fencing and ironwork. Thanks for your great work on this I can’t believe how easy it is to get quite usable results for many different types of objects using this.
I was wondering is there a performance hit to using sub d thicken instead of curve piping? If I have a lot of sub d thickened curves any way to optimize them all or thoughts on that?

Do you mean compared to the curve piping display option in the object properties?
I think that will generally be much quicker than any method like Pipe or SubDThickenCurves that create actual NURBS or SubD geometry in the document.

I’m also looking at giving an option for a mesh output from the command, which should be lightweight, for if you want to be able to spin around models with thousands of thickened curves. This mesh could also be subdivided once or twice (but still producing a mesh rather than an actual SubD object) to give something a bit smoother but still light.

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