ToSubD with Location is great but it alters the mesh... :(

Hi guys, (@dalelear @theoutside)
when converting a simple mesh to SubD the “Location” setting instead of the “Control Point” is great for interpolations:

BUT this alters the subD cage to something else than the control mesh, making it impossible to add new accurate location points. I fully understand that this has to be done under the hood, but for a user it is not much good IMO.

I know I can turn on EditPoints instead of the ControlPoints, but when I swap from smooth to jagged view (Tab) then I see the distorted mesh. So COULD this be invisible to the user and have Rhino show me the input mesh instead?

I understand this would require a dual setting for SubD’s, but with out it it’s close to impossible to use “snaps” for SubD. I guess SubD objects would need a toggle to choose what mode to use though…

As you can see, if I make a crease on the “Location” SubD then this crease is now NOT where the original input points were, it is along the edge of the “altered control mesh”:

The problem now is that I can’t manually move this creased edge up to the original location either since then the SubD won’t align to the surrounding location points any more.

I see this is a bit complex so shout out if there is anything that needs clarification.


Adding creases always changes shape of the nearby SubD surface - it doesn’t matter how the SubD was created.

I think I understand the workflow issues pretty well.

For the interpolation to assign the topology AND location you’re hoping for, I would need to know what crease attributes you planned to set before I do the interpolation. This complicates a command that is working good enough as is to ship 7.0. We can address this workflow after we ship 7.0.

We could also add complications to the point editing and I imagine that will be required. But again, it’s going to happen after we ship 7.0.

Thanks for pushing SubD and I hope we can get to this reasonably soon.