Struggling with UVs and UDIMs in Rhino 8/Rhino 9

[AlanMattano (Soaring Stars lab)]

AM52
Struggling with UVs and UDIMs in Rhino 8/Rhino 9

Example: Created this sailplane glider variometer with Substance Painter textures requiring multiple UDIM tiles (1001 and 1011).

Issue: No way to assign textures to second UDIM column directly in PBR materials.

Workaround: Split mesh into sub-objects per tile: offset UVs to 0-1 space, duplicate PBR materials, adjust texture offset (U=1 for second column), assign separately.

Problem with workaround: In UV Editor, can select faces with UVs in second column (U>1), but selection doesn’t persist when closing editor or switching viewports. Can’t extract/copy selected faces while editor open, and no way to reliably re-select them afterward for ExtractMeshFaces without guessing.

Editing polysurfaces (extrude/cut) destroys custom UVs.

Is native UDIM support planned? Better way to select/extract faces by UV range?

WIP Iray rendering

[theoutside (Kyle Houchens)]

@Jussi_Aaltonen may want to peek at this thread-

I’d love to connect you two together to discuss this as I feel like you have a very in depth workflow using these tools.

[jesterking]

RH-69319 UDIM support for texture mapping

Not planned, but on the wishlist.

[AlanMattano (Soaring Stars lab)]

lol Thx!

Issue: Closing the UV Editor deselects the preselected UV mesh

@Jussi_Aaltonen As a quick workaround, what we need is that, selecting the UV mesh inside the UV Editor before closing it keeps the actual mesh selected in the main view. This makes it easy to isolate the mesh for each texture.

AM52 closing the UV Editor deselects the preselected UVmesh

[AlanMattano (Soaring Stars lab)]

Not sure if this is the workaround.

Texture mapping a wood floor

Hi @rkwill I’ll try to explain one way - not saying it is the easiest. But perhaps something you can try to get the job done. I made a polysurface and assigned a material to each face - you can do this by sub object selecting (ctrl + shift + left click) the face and then selecting a material on the object properties material tab. [image] Then I enabled multiple mapping channels for that polysurface and filled channels 1-3 with planar mappings. [image] Then adjusted the mappings by showing …

[Jussi_Aaltonen]

@AlanMattano

Problem with workaround: In UV Editor, can select faces with UVs in second column (U>1), but selection doesn’t persist when closing editor or switching viewports. Can’t extract/copy selected faces while editor open, and no way to reliably re-select them afterward for ExtractMeshFaces without guessing.

The highlighted mesh faces in the model view can’t be directly selected. I’ve logged this YT for the problem and will soon add a hidden command to let you get from UV island selection to mesh sub-object selection.
RH-91095 Select objects by UV island selection

[dan]

RH-91095 is fixed in the latest Rhino WIP.