Sub D to Nurbs - clean surface?

how crazy are you zbrush models? are they relatively mechanical parts, or are they insanely detailed 200million poly models with micro textures on everything?

throw up a typical example and I’ll give it a go…

my thought is that exporting a quad dominant model from zbrush may convert to subd as long as you are not bringing in 200 million polys…

if so, then decimate it in ZB, then bring it into rhino and quadremesh it and try the nurbs conversion/ pack from there. I’d prefer you burn up your cpu testing this instead of mine, but I’m game to give it a go… I’ll keep the extinguisher handy…

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Yeap, you could do it that way. Or wait for the details to be Curves on the Polysurface solid and use the PanelEdges capability to have dynamic details on the polysurface.

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Is this command available in the WIP already? I can’t find it.
rhino say unknown command…?

thanks a lot

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Passed on Rhino WIP for Windows (7.0.20248.23555, 9/4/2020).
Passed on Rhino WIP for Mac Version 7 WIP (7.0.20248.08006, 2020-09-04).


Thanks @inju
I see you have a newer version then mine…?
I have 20245. from last Wednesday. and you have 20248.
Strange as I’m getting the < your version is the newest one available > massage.
Are you on a VIP build? [daily version]

thanks a lot


Hi Scott, Sorry I don’t understand what you mean here?

thanks a lot

I am sorry I was not clear. It is officially called shut lines :

It might work too modify the object after converting it to NURBS.

Hi Kyle
Thanks for volunteering to sacrifice your hi-preformance computer on the altar of TechSupport.
As my 2013 MBP does not even qualify for minimum hardware requirement.

I’m still finding out and learning the Rhino & Zbrush pipeline
I try to do the jewellery body [main parts] in Rhino as long as that makes sense, and then send to Zbrush for sculpting / ornamentation / engraving. Basically just doing on the computer the sort of work I used to do by hand directly on hand fabricated gold part.

Haven’t used Nano Mesh or HD geometry in ZB yet… so parts can go up to 20 million perhaps for the required resolution.
and yes, it then can be Decimated a lot without losing any details.

So the big wish is if there was a way to bring Quadremsher in Rhino to take the decimated geo, and convert to SubD using the same idea! meaning large faces where possible, and very small [subdivided] faces in the areas of small details.

Here from hi poly

to Decimated geo with dens areas where small details are

unfortunately Zbrush does not maintain quad geo when decimating. But rhino could do it! as subD have no problem with Ngeons so the border between the dens details and the large faces is [in my user logic] possible.

thanks a lot

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Hi Scott
I tried to experiment with shut lines [first time thanks for opening that door] But I’m not sure how this can be of use in my work… it’s a render mesh thing, so it does not actually being applied to the nurbs part.
For curving in mesh, ZB, is no match really. this is one of the main reasons I work with it together with Rhino.

thanks a lot

Try the extractrendermesh command and you should get the modified mesh.

This is just experimenting with workflow. When are NURBS required and when are meshes required? What is the final fabrication technique?

All this new tech allows us to go back and forth much easier then before. But it also creates a lot of questions about the most efficient workflows.

Apology, my last reply may have not been written well.
I can’t at this time imagine a scenario in my work where I would want to modify mesh in rhino [apart from quadremeshing to subD] I have access to ZB so why would I want to struggle in rhino when it comes to things like ornamental engravings…?
The issue I raised these questions was in regards to arriving at the optimum way of getting the ornamented mesh into rhino Nurbs where possible.

again apology for misunderstanding, I’m not always very good communicating.

Mostly it will be STL for jewellery printing.

Yes, and this makes it very interesting and relevant to my [Still developing] workflow.

work flow sequence [as far as I found out by now]

  1. Making main parts in rhino [nurbs + subD] > then sending a very dens .obj to ZB for ornamentation and other work. > then rendering [Keyshot] and decimating dens mesh to .stl
    [I may open the .stl in rhino just for inspection but won’t modify it in any way.

  2. But often, the ZB mesh will need to go back to rhino for gemstones setting and other precision needs [or simply to add a part that I’m more comfortable making inside rhino].
    At time I can make all these parts separately and leave the ZB mesh unmodified [inside rhino] then take all back to ZB for Live-Boolean and finish the work in there.

  3. Yet, many times it would be [now already possible with simple geometry] very helpful to go back with the mesh to rhino nurbs.
    I tried to imagine a way this can be developed to work for very detailed parts as well. [wrote it as a replay to @theoutside. above in this thread]

thanks a lot
with best regards

Could the “packed” option be also be implemented for the regular Rebuild command?

(Also, why “packed”, which to me, as a non-native English speaker sounds denser than the original, when it from the outside looks as if it should be “optimized” or as the topic says “clean”?)

I am not sure which conditions must be
satisfied for data conversion to occur correctly.

In my think Sub-D --> ToNURBS very NICE.

Test Rabbit is Rhino Forum User up-load file. Thank you~

I wrote a bit about adding face packing to general Nurbs surfaces there: Packed Faces options in Rhinocommon and/or for regular polysurfaces. If you have examples of workflows where this would be useful to you, I’d really like to have a look at them.

“Packed” here is in the sense of a tightly bound group of faces. When we are packing faces, we are grouping a contiguous rectangle of faces into one big surface. The problem with words like “clean” or “optimized” is that they will mean very different things to different people (i.e. are your criteria for a clean surface the same as mines? what value are we optimizing for?), so using them leads to misunderstandings.

How about ‘merged’?

I’m running an older WIP due to circumstances, but it seems that “packed” sometimes ignores sharp edges:

Hi Robert -

Without an actual file, I’m afraid there’s nothing for us to try and reproduce…

Hmm… I can’t actually get the same results now… guess why that’s still beta…

Using and commenting on an older cut of the beta is not useful. Please update and test this again. If it’s still a problem let us know, as we need to get it fixed.