SubD Progress

Good job on the SubD development! I tried V7 months ago and wasn’t all that excited about how things felt. But the recent progress will give me just about everything I need to replace Fusion 360.

I model SubDs in Modo (that will be a little tough to give up:-) and then export OBJ to Fusion to convert to Nurbs and then into Rhino. I tried the same with V7 and had no problems or issues getting what I needed. One request would be that the nurbs patches get simplified…as it does in Fusion. It makes for easier filleting and other detail work when not having to work across patches. I’m sure it has been mentioned.

But all in all, very positive development and will be a no-brainer for me when released.


Thanks for the feedback Paul… I added your vote to the open item regarding patch size on NURBS conversion.

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Can you show me an example of what you mean by “simplifying patches”?

I’ve noticed that a flat pentagonal subD face, surrounded by creases, yields a triangle fan when converted to NURBS, which will simplify if MergeAllFaces is called. Is that what you mean?

Also, related: conversion from mesh to SubD and vice-versa in Grasshopper seems to triangulate SubD faces.

Here are some screen shots of the original 00 SubD Cage from Modo, then 01 is from Fusion converted to Nurbs and then 02 is the cage converted to subDs and then to Nurbs in Rhino. It looks good but there is the potential issues of booleans and fillets across multiple cut curbs patches. Being an illustrator, the resulting image was created from Modo>Fusion>Rhino>Maverick Render.


@PaulS first, great render as always. Second @pierrec is working hard on making those simplified patches happen.


@Brian James, You can add my vote to that as well. It’s one of the main reasons I have not purchased Clayoo after T-Splines went away. Instead I got Fusion 360 with T-Splines. Unfortunately for me, the T-Splines functionality in Fusion is still not up to the same level as it was when it was a Rhino plug-in.

Been playing with the WIP in the last few weeks and it has great potential, but a larger patch size would be very important in my opinion.

In addition to this, with T-Splines for Rhino you could actually select your own edges prior to conversion so you could create a patch layout that was optimized for after conversion workflow.

As an example large curved sections with many subd faces could be deleted and replaced with a loft/blend srf/sweep2 or something else. It is often near impossible to get good curvature flow going through a lot of subd faces and replacing them afterwards with one clean single NURBS patch improves curvature flow. While the individual transitions between subd faces may be curvature continuous, once you add several together it is near impossible to get a smooth curvature comb going through all of them.

p.s. I still have Rhino 5 with T-Splines, if you need some images or other information that may be helpful, please let me know.


Thanks for the feedback!.. I added your post to the feature request as well.

Are you saying that getting good curvature flow through a lot of SubD faces is hard because of the nature of the junctions between them? or is it because if vertices aren’t perfectly aligned you get dents and bumps?

In the WIP, I’ve gotten seemingly very good curvature across multiple subD faces by using guide curves with good curvature and near-snap to move vertices onto the guide curves. Being able to automatically move a row of vertices to a guide curve or a guide plane would be awesome. I can see a path to doing that with Grasshopper once SubD is fully integrated using the curve closest point and point deform components. But being able to do it with a rhino command would be really cool.

@Max3, it’s the second. If vertices aren’t perfectly aligned you get dents and bumps. Depending on how many SubD faces you have it can be quite a tedious and time-consuming task to clean this up or improve.

As far as aligning stuff, Here’s something I have found quite useful. In Box-mode you can use BlendCrv on the SubD control cage edges. After you create the blend curve you can use @pascal script AlignGrips.rvb to suck the control points to the blend curve. The command you need to run is AlignGripsCrv. Works quite well.

The other thing that works with SubD Control points is ProjectToCplane, this too can be used to create orderly Control points. I’m playing with this to see what Rhino commands work and which ones don’t, but there are some cool options already and I’m sure I will discover more ways to improve the modeling workflow. I see some Rhino play time in my Thanksgiving weekend, this is super exciting to me.

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SetPt (one axis only) ought to work well as well for similar cases.


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Yes, that’s another one that I have used. Also for now I use SetPt to fix symmetry issues. When used with two axes. This is not ideal, nor perfect since it’s both time-consuming and you can’t control the third axes, but at the moment that’s what I’m using.

Wait, can you explain the align grips thing a little more? or is there another thread about it?

Here, copied from another thread. both scripts are quite useful for control point modeling and they both work on SubD vertices

Hi Keith - I use a script for this - pretty ancient but it may do something useful.

Unzip, save then drag and drop the rvb file onto Rhino - there will be two new aliases

AlighGrips - lines grips up to a line defined by two points (user input)
AlighnGripsCrv - sucks selected grips onto a curve.

Both work either by closest points or in a user defined direction. (1.4 KB)



One additional comment.

Converting to SubD and then to Nurbs in Fusion 360 I error out if I have a ‘self intersecting’ poly cage.

Rhino allows for the process to continue without error messages and ultimately failure. Success!

super happy to see progress when it comes to subd-s in Rhino (and totally love new quad remesher).
If you’ll be able to get optimized conversion from subd to nurbs on release (“grouping” faces in bigger nurbs parches, not converting each poly face to separate nurbs patch) you’ll have a winner.

If at one point you’ll be able to get proper subd edge weighting working so we’d have something better than regular crease and you’ll add ability to create insets with gumball that would be even more awesome (at this point you need to extrude forward / backward slightly and then use scale handle, then move the face back to position - super unwieldly).

Thanks, I added your votes to the open issues on the pile for larger patch conversion and weighted creases.

For GB inset, try align to object > Scale 2D via Shift and then press Ctrl/Cmd to create a new face.

wait, you can 2d scale with the planar move widget? You’ve just made my day :smiley:

So I have been trying to figure this out as well and for the life of me, I couldn’t figure it out. Used the same method as @Przemas, extrude out, scale in and move back. This is not very discoverable at the moment with the combination of keyboard strokes that are required.

Happy to know about it, but I have a feeling quite a few users will struggle to figure this out.

I often project vertices to construction plane and delete input, works good. I also like Transform Align Tocurve. Would be nice to be able to project vertices to a nurb surface.

I do that too, but it’d be nice to be able to draw the plane inside the Align command rather than changing the cplane, aligning, and changing it back.

It should be like the _3point option in the _Mirror command.

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