[FEEDBACK] V7: Joining surfaces does not lose its individual texture mapping unwrap

I was trying to make a custom Unwrap but was not cutting along the selection. It looks buggy. And I was not able to make individual custom unwrapping for a polysurface (or I do not know how to use multiple mapping channels). So the object was divided it into 3 different polysurface and apply different mapping technic to each one. But when I use “join” I lose its individual texture mapping unwrap.

I wish an option in “join” that allows preserving the texture mapping and (automatically) assign each one to different channels in the final polysurface. This option can save me some time and can be simple to understand for how do not understand how to configure and use texture mapping channels.

NOTE: In-game dev and VR presentation we need to limit the draw calls. So we need a joined mesh.

At the moment the only solution i found was to export the meshes as FBX to Blender. Then “join” them there and return back as OBJ. Since Rhino export beautiful and perfect custom vertex normal maps is better to preserve them across the workflow. Blender FBX exporter is applying vertex normal recalculation that change the final vertex normal. Blender OBJ exporter is working well for vertex normals.

To resume: Using just one UV mapping technic is not geometrically feasible or aesthetically desirable. If I create different polysurface (with individual UV mappings) later I can’t join them together. If I can´t join, then when I convert to mesh, it creates holes between meshes. So the way left, for making a mesh without holes, is by using one UV mapping technic.

Hello - the way out, if I follow, and I know it is not what you want, is to mesh the object, explode the mesh and then map the pieces as you like.


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@AlanMattano I don’t use Rhino 7, but at R6 you can export your single meshes as OBJ and the mapping is burned in the mesh. Load it back to Rhino and join them now - your mapping should be kept.

Your problem was, you tried to combine several different mapping into one, like a spherical mapping and a box mapping. It can’t work. But if you burn the mapping in the UV, than you can join the meshes, because every object has the default surface meshing type.

Yes Pascal, Actually I’m manually selecting seams of mesh containing 65.000 tringles each one. But Imagine a car, aeroplane, sailboat, that includes interior instruments, engine included. I know you know but is just for who is reading this thread as a developer.

As you can imagine is not humanly possible to work with meshes containing a million of polygons. And I or we need to deal with that in the next years. So I’m preparing myself and the environment (Rhino) for that. With my little englis, I’m isolating and reporting bugs to fix a simple workflow that allows the conventional user to unwrapping (or unpacking UV mapping) the polysurface (using the surface edge as a seam) instead of the mesh as it should be. So I’m pushing just to fix some problems as a better solution. Thanks @johnc for fixing RH-54101 that is a time saver for a lot of users.

@Micha I will try that. Yes, combine several different mapping into one without creating holes into the mesh and doing all inside Rhino instead of outside. I will try that OBJ. What do you intend for: default surface meshing type? can you expand that?

I have something overseen - you like to work with NURBS all the time, right? Export and reimport as OBJ works for meshes only. I read something about games and meshes, so I thought it’s your goal.

The problem for you is that a Rhino object can get one mapping only. You if join an object with mapping A and one with mapping B, than you lost one of them. My trick works for mesh objects only.

If you could work with meshes, than your life would be easier. First you create a mesh for the whole object. So, you don’t get holes. Than you extract the needed sides per _ExtractMeshPart and assign your unfolded mapping. Now use the OBJ export-import and join the mesh parts. So, you could get a mesh without holes and hand made UV.

Sidenote: If you should need more advanced unfolded mapping, than you could think about a software like this:

I use an old version of this software. Also MoI3D helps me a lot to get high quality low poly meshes.

As opposed to polygon mesh based applications, the main point of using Rhino, since its origin, is that Rhino takes care of mesh side while working using surface.

@Micha I try virtual space but not REAL space. I’m unable to try Real Space because RizomUV gives you one shoot for computer to try it and probably I choose the wrong one (virtual).

With virtual space, I was losing Rhino vertex normals after unfolding UV mapping. Also, when importing FBX, a Message pops up sometimes “unsupported mapping mode” (enclosed file example) Rhino.rar (52.5 KB)

Are you able to preserve vertex normals using Real Space in the workflow?


I use an old Unfold3D, it is the software before the developer and the company owner split the software in two new companies. Rizom is created by the “old” developer. So far the background you don’t ask for. :wink:

I can’t remember to got vertex normal issues.

Your example is using FBX. Maybe there is an issue with FBX connection. At my old version OBJ is supported only. So it looks if I create a mesh from the NURBS object and unfold the OBJ without any additional cuts.

What is your goal, for what do you need the unfolding process? VR per Unreal?

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At first, in the 90s I was using Alias but when it split into Maya I stay with Rhino

I need to unfold my own 3D gliders, this sailboats and Pininfarina cars. Complex surface and meshes with full of detail.

My own VR world in C# because I can make presentations using physics and testing interaction or performance [DAD]. Unity as an engine. I was developing this in Unreal since first UDK and then I switch like 5 yr ago.

My actual workflow is Rhino > Painter > Unity > Flight Soaring Simulator build or Asset Store
Sometimes Rhino > Blender > Rhino > Painter for fixing or retopo.
The workflow is using FBX but since now Unity 2017~ and Painter 2019 support OBJ I need to try it.

Latest 2019 demo of Unfold3D crash when importing FBX.
And RizomUV give an error “unsupported mapping mode”.
I will try OBJ workflow. But FBX was more a standard.