SubD Reflect & Creases questions


currently working on my first job in Rhino 7 with SubD.
Overall it works great, but I hit some niggles:

When I reflect a SubD, I am unable to create creases on the centerline edges.
I can select them alright, but when I hit the “Add Crease” button, nothing happens.
Since I work a lot with creases, that’s a bit of a bummer, since I need to remove the reflection, apply the crease and re-create the reflection.
Is there a trick to get this working or could this be improved otherwise?

I’m also not really happy about the inability to work on the greyed out side. It’s not so much a problem in perspective view, but it makes working in planar side views more complicated, since one has to toggle to the front/back or left/right depending on what side is editable.

And a feature request: I’d really like to have edge weights to be able to have semi-creased edges. For instance in Blender it’s a continuous float value between 0.0 and 1.0, where 0.0 = no crease and 1.0 is the same as the current sharp crease in Rhino. The in-between values allow for increasingly sharper edges.
This is very handy since it allows for what could be called “organic fillets” that have nice tangency and flow with the overall SubD structure.
The ultimate implementation would allow for changing weights along edges, so one can go from fully smooth to fully creased in an organic manner. I’d use that to death :wink:
Could work a bit similar to variable filets, but for me it would be enough to be able to set the weight per vertex along the edge.
(And yes I know that I can add more edges to get the same effect, but that starts to get messy fast and is pretty hard to modify later on).

Thanks a lot!



Hi Tom - thanks, I’ll add your comments to the bug tracker. I believe weighted creasing is on the ‘to do’ pile for SubD - if not, I’ll add the wish to the heap.

RH-63366 Crease: crease on the reflection plane

RH-63368 Reflect - allow editing either side

The weighted creasing item is there and I’ve added your ‘vote’ but at the moment it is not a public YT item due to some client reference info in there.



That would be great!

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Thanks a lot Pascal!

I do SubD modelling since 2000 when the first beta of Lightwave 3D 6 came out that introduced live-modelling with “Metanurbs” by Fori Owurowa, so it’s my way to design for ages - good to finally be able to use them in Rhino too! :slight_smile:



This would be a big deal. I know NX has a weighted crease tool on their subdiv implementation as well


Oh and just to add one more thing: Softimage XSI had a way to treat triangles differently than quads and n-gons and Rhino SubDs deerly need such a better solution for triangles.

ATM, Rhino creates the typical SubD-Mess of a naive implementation of Catmull-Rom, so Triangles create weird folds and distort the surface flow in usually unwanted ways.

In XSI, there was an option to use a kind of “loop” interpolation instead on triangles, so they were interpolated not with quads (which creates the mess) but with triangles. They had the smoothest SubDs I’ve ever seen (of course until Auto-fucking-Desk threw it in the bin).

While Triangles can - and should - be avoided as much as possible, sometimes it’s either just not possible or creates a different kind of mess.

Rhino is on the right track with integrating SubDs into CAD, it’s high time for that to finally happen, but it should also do better on surface continuity.

And then of course there is the rather naive conversion to NURBS, but I leave that for another post.



@pascal Hi, is the e->m_sharpness value is kind of edge crease weight?

Hi Guys, I’m in the middle of updating some older designs from R5/Tsplines to R7/SubD and have run head on into this bug.

Any idea when it may be sorted?



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