Rhino 6 - T splines - Z Brush Problem


(Joaquin Laborda) #15

I can’t guarantee that but it should have this feature if it wants to be an alternative to T-Splines.

Z-Brush has a lot more powerful tools than Clayoo for sculpting, but this doesn’t mean that this plugin can’t be ideal for people who want to do all inside Rhino.


Hifred thank you.

I know people who do it for jewelry. But I’m guessing the nurbs program will simplify it a bit. Since Rhino can’t convert mesh to nurbs, I need a reliable in between program that will.

Any suggestions are welcome.


I’m sure it’s a good program, but it’s bought by another company and there’s no guarantee they will keep supporting it. It’s a dilemma.

(Wim Dekeyser) #18

Like I said before, if the kind of mesh to NURBS conversion is the T-Splines kind, you will be able to do that by converting meshes to Rhino’s SubD and then to NURBS. See this post for more information on the status:


Thank You wim.
Will I also be able to do the reverse and convert nurbs to mesh?
I need to read up on subD. My goal is to bring ZBrush meshes into Rhino. I’m not sure ZBrush files are the same as Tsplines. I need to learn more about the file types.

I’ve also gotten word that I can upgrade to V6 and still keep V5 with tsplines. Then it’s just a matter of bringing a V5 file into V6.


Here are a couple older threads, but might be helpful:


@Paul_Bundarin I was working on a Rhino to zBrush workflow about a year ago. I will look back for any info. I was using T-Splines as well, but the OBJ file I exported from Rhino was after the T-Splines had been converted to NURBS. The OBJ from zBrush can be imported back into Rhino no problem, if I remember correctly.



Well, all people mean something else when talking about complex.

What can’t get done is taking a Zbrush mesh with millions of faces and convert it straight to Nurbs. None
of the people you know does that. Tsplines or any other converter will just freeze and you will have to
kill the application.

Obviously one can still use Zbrush and Rhino together nicely. If one really needs to convert the Zbrush mesh to Nurbs one had to stick to far lower resolutions – and as Wim stated the V6 converter should do (SubDFromMesh).

But you could also load a very heavy Zbrush mesh and simply keep it as a mesh. Converting to Nurbs doesn’t make it any better / more valid / more precise. You still may combine your Zbrush source object with some Nurbs geometry. The final product will likely end as a mesh anyway, for wax printing or similar, no?


@hifred With all my searching I have learned that T-splines is no longer available and Clayoo is now a subscription product.
So you think the SubDFromMesh will accomplish the same transition if I work in a lower resolution? Will I be able to do the reverse and convert nurbs to subD then bring it to Zbrush? I’m wondering if that will suite me or will I still need an organic modeling program like T-splines? I won’t consider subscription programs.
I also feel that I have more options for editing an object in Nurbs format.


@Paul_Bundarin I do not think that is correct…but I have been wrong before. Clayoo can be purchased as a stand alone license AFAIK. I don think any of TDM`s products are subscription based.

The 1 year subscription mentioned on their website is to their premium level support/education products.

12 pm27 pm

(Nic Kuipers) #25

Hey Paul,

You’re getting in deep when exploring transferring Zbrush files into anything else and any solution is inevitably going to be complex.

I’m an industrial designer and I often work between Zbrush, Solidworks and Rhino for highly accurate CAD work, mixing accurate data and the inevitably less accurate Zbrush work. The problem arises when bringing Xbrush files out of it and into anything else, as Zbrush functions at higher resolution levels that any other program I’ve ever used (or heard of!!!). This becomes a problem for other applications as they don’t have anywhere near the processing power to handle all the polygons.

In exploring a Rhino-Zbrush workflow I’ve realised that I’ll never be able to work with a Zbrush surface in any other program effectively, so this is how I work around it:

  1. I decimate my Ztool heavily (I mean 1-5% of the original polycount) and then export to obj (I don’t want details, I just need overall forms to help me model later.
  2. Import the obj into Rhino
  3. Make sure that Osnap “vertex” checkbox is on down the bottom of the window, this allows me to snap to mesh geometry without converting to nurbs.
  4. Model what I need in Rhino
  5. Export to OBJ from of Rhino at really high resolution.
  6. Import into Zbrush and use the decimated original body to line everything up.
  7. cut/combine/project details from imported Rhino model onto your Zbrush model. Dynamesh will be your friend!! If you’re not familiar with it, there are lot of good tutorials out there.

Unfortunately any solution going between Nurbs anything and Polygon anything is a very imprecise (and totally manual) art. It’s more trial and error than any real method.

Hope some of that helps!


this may be interesting

bye Riccardo


@sochin Is this price from the CAD Jewelry School? Have you purchased anything from them?

Are you working with Clayoo? Do you think it’s the best substitute for T Splines?



Well, SubD is new and not even officially available inside Rhino.The included converter still is in extremely raw state. It essentially replaces every single face in the SubD-cage with a Nurbs surface. More mature converters such as Tsplines try to create a usable patch-layout but no product outputs good Nurbs models in the sense that one may perform demanding surfacing operations on the converted model. If the goal is to cut some holes and possibly to create some simple fillets here and there this will do though.

This is the Zbrush sample dog converted to Nurbs with the V6 converter and with a precise hole cut into its belly. You can try this out right now by loading a quad mesh to the Rhino 6 Beta. Run the SubDFromMesh command, followed by the ToNurbs command.

If that all sounds too raw for you may use Autodesk Fusion for Nurbs conversion but that is a subscription program.There’s quite a bunch of other Mechanical CAD and dedicated Reverse Engineering programs which let you convert quad-meshes to Nurbs but they are very expensive + a lot of of them are subscription based these days. None creates a Nurbs model which allows for advanced modifications.

I can’t speak for McNeel but I dare saying No.
There’s no program which lets you freely convert models back and forth between SubD-meshes and Nurbs.
Rhino 6 won’t let you do this either.

Good news is that you can sculpt any Rhino model inside Zbrush. With Rhino 5, today.

I think you are mixing up techniques and terminology here. A SubD cage is a mesh with a particular topology with just four sided faces. Not all models with just quadrangles are SubD-Caged though. Meshes with such topology are ideal for smooth subdivision. But Zbrush will work just fine with any sort of less regular meshes as well. If the input is really bad there’s great ways for remeshing. If you want to bring the modified model back to Rhino you may simply re-import (I usually have no problem with the full resolution data and rarely have to use decimation). If you really need a Nurbs conversion you can create a conform mesh inside Zbrush.


@nic.kuipers Thanks for the info. I was assuming I would have to convert to a low res to be able to get into Rhino. I guess that would be trial and error to get the most detail possible. When you import to Rhino to work on it are you editing meshes in Rhino? What about converting to nurbs for better editing possibilities?

Do you have 2 versions of the object? I’m a little confused.

(Wim Dekeyser) #30

Apparently, SpaceClaim seems to claim that they do. Does anybody here have any real-world experience with that? @DanBayn?


Was The dog originally made in Z Brush? It looks pretty good to me. Do T-Splines and Clayoo work in subD quadrangles?
I have been under the impression that in order to do good editing I would have to have a nurbs surface to work with.

What kind of file are you re-importing? > Blockquote
Would having an inbetween program like Clayoo help with the transition? I’m assuming Clayoo is also quadrangles?


Hi Wim,
the clip on the page you linked shows a purely Nurbs based Reverse Engineering process.
There’s no Subdivision Surfaces modelling whatsoever involved.

In fact there are some CAD programs, such as Autodesk Fusion which allow for a limited back and forth conversion between Nurbs and SubD-Cage. Fusion stores the editing history – after applying some Nurbs features one may go back to the Control cage and deform it. When done the pre-existing parametric features get re-applied.


It is one of the sample models which ship with Zbrush.

That is a very broad statement.
Skilled modellers may produce very accurate models by Nurbs Surface modelling, that’s true.Less precise geometry representations on the other may be more inviting for quick design iterations. Sculpting programs like Zbrush allow for a sort of geometric complexity which can’t be achieved by any other 3D modelling process.

This guy creates and manufactures his jewelery only in Zbrush. No Nurbs conversion involved.
These baroque and roccoco furniture are modelled in Blender, also as a mesh.

Stuff like that would be a bloddy nightmare with Nurbs (not just in Rhino) So good editing depends.

An .obj works just fine.


As @hifred mentions, you may not need a nurbs surface at all. This really depends on your intent and manufacturing method.

I don’t have experience with any poly to nurbs converter that will give editable nurbs curves from an organic object by an automatic method. I recently saw video of a Rhino plugin, Surface2Mesh that looks like it may have a faster method of generating the curves than doing it manually. Maybe someone here has used it.

PowerSurfacing RE (for SolidWorks, no Rhino version yet, The stand alone version is Cyborg3D.) can extract a subd control cage from a mesh to create a nurbs surface. Then the nurbs surface can be snapped back to the original mesh (not the subd) to preserve the finer details.

The nurbs surface produced by T-Splines, Power Surfacing, and I believe Clayoo as well from an organic object can only be edited with the specific application. The export is a dumb solid, which is the same as the result from a more expensive solution like Geomagic Wrap/Design X.