Wish: SubD option in circle command


how to draw a SubD circle? A SubD with segmentCount option in Circle would be nice.

Or have I missed something?



How would the control point layout of a SubD friendly circle differ from a normal circle?

Why draw a circle when you can use the SubDCylinder command?

If you extrude a Circle or Deformable Circle you’ll get an extrusion by default, ToSubD can be used on that and you’ll get a circular SubD as an alternate workflow to SubDCylinder. Let me know if there was something else you were trying to do with Circle.

Hi Martin and Brian,

when I extrude a SubD-friendly curve with the Gumball I get a SubD.

When I extrude a deformable circle (subD-friendly curve) or normal circle I get an extrusion. I would search further to find this SubD circle, because of my old approach to start.

Yes, SubDCylinder and converting works ( I think I can live with this. :wink: ).



I see, yes… you would need to rebuild the Circle into a SubD friendly curve in order to get a SubD when extruding it. I suppose SubD friendly could be an additional option when Deformable is chosen. That way it would make a SubD when extruded. Is that what you were after?

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Yes, that’s what I am looking for.

I am confused, because a SubD-friendly curve extrudes to a SubD, a deformable circle not, even when it’s SubD-friendly.

Even worse, when I use ExtrudeCrv with my deformable circle I get a SubD, with the Gumball an extrusion. Hä?

I would rename the circle deformable option to “deformable and subD-friendly”. OK, a little bit long. :wink: And change the Gumball extrusion to extrude all SubD-friendly curves to SubDs.

ExtrudeCrv has an Output option, you must have used SubD last time. I’m actually not sure if a deformable circle changes any at all being SDF or not. It may just be a tag on the object that lets commands that make surfaces know that a SubD should be made. Filed as https://mcneel.myjetbrains.com/youtrack/issue/RH-58772

That should work already… post a curve if it doesn’t please.

I’ve found the Output-Option in ExtrudeCrv, sorry.

Attached a deformable/SubD-friendly circle, which extrudes with the Gumball to an extrusion.

deformable_circle_SubD-friendly.3dm (60.4 KB)


Thanks, I filed https://mcneel.myjetbrains.com/youtrack/issue/RH-58784

Hi Michael, I found out from the developers that this is actually by design. A curve can be compatible with SubD creation but is not assumed to be used for SubD creation. Here’s what they said…
“There are 2 kinds of SubD friendly. Some curves are specifically tagged as such. They are then listed as “Subd Friendly+”. Other curves may be compatible with SubD (=degree 3 uniform curves), but are not specifically tagged, and cannot be assumed to be constructed with SubD output in mind. Those are listed as “SubD Friendly”.”

I learned something too, thanks for bringing it up!

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Hi Brian,

good to know.

Shouldn’t the Gumball extrusion have an option for different results (extrusion or subd)? Gumball extrusion looks now like gambling to me.

Thank you and have a nice weekend


The idea with SDF crvs was that they would automatically create SubD surfaces when extruded. This works now but only if the curve was made as SDF or rebuilt to be SDF. Otherwise, getting an extrusion versus a NURBS surface is a global setting with UseExtrusions. If the GB picked what got made and you set it to SubD, the result wouldn’t always match the curve which I think could cause more confusion.

I think slowly I get it, sorry.

SubD-friendly+ extrudes to SubDs with the Gumball, SubD-friendly not.

Right and only because the SubD-Friendly label in the object details only indicates that it is a SubD compatible crv but not that it was created intentionally as a SDF curve. The Curve command or Rebuild allow you to make a SDF curve on purpose and those will have SubD-Friendly+ in the object details. If we can add the SDF option to deformable circle creation hopefully it will be less likely to cause confusion.

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