Hi All,
Here’s a new video on the updates and improvements in the UV Editor for Rhino 8. Enjoy!
Excellent video @BrianJ . Thankyou.
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Thanks!
Clear, precise, quick thank you Brian
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Awesome!
Although I wonder if it all went as smoothly as seen in the video 
Very good video, thank you!
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Wanted to take the time to thank the people at McNeel for the improved UV editor in Version 8.
It is truly a gamechanger for handling nurbs UV mapping.
So much better than Keyshot’s clunky solution.
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So glad you like it! Please keep sending us feedback on how UV mapping can be further improved, it’s a topic that we are keen to continue development on-
@BrianJ First of all, a big thank you for the very interesting video, which taught me a lot. I have a few questions and requests.
Symmetry - it would be nice if the result was more symmetrical and the polygon edge on the mirror axis was straight.
The fact that you can align a UV mesh to curves is great. On the other hand, I used Unfold3D for many years and I would have unwound the UV mesh first, then relaxed it and used the resulting unfold as the basis for creating a texture. I think often you don’t know what the relaxed UV island will look like and when I align the mesh to a shape I estimate, I distort it more than to be expected in reality. I miss a relaxation function. Or does it already exist?
You first align the lower edges on the left and right. That’s how I would have done it in Unfold 3D. Here I wish I didn’t necessarily have to use a curve as a reference. In Unfold3D I can choose between simply fixing horizontally or vertically (in Unfold3D there is no alignment to curves). Would this also be possible for the Rhino Unwrap tool?
After fixing the lower edges, I would press the Relax button in Unfold3D, which would minimize local squeezing/stretching. My goal is not to specify my shape, but to achieve the most physically correct unfolding possible. At the moment in the screenshot above, relaxing would provide the ideal result. Could add a relaxation function implement to Unwrap in the future please?
One more example where simple horizontal/vertical alignment would be useful - in the final result I notice that the top center ISO line is not straight in the middle. Here I would select the polygon edge in Unfold3D and set it to vertical.
A relaxation function would also ensure that this local stretching at the seam would disappear by itself.
I know, unwrapping is a science in itself and not easy. It would be nice if a relaxation function was possible and I hope a horizontal/vertical alignment is easy to implement.
After I wrote all this, I had a direct look in Rhino and it looks like my wishes might already be possible, there are still tools hidden there. 
Is there a video about this?
I took a closer look at the edge straightening. It would be nice if it could be preset to horizontal and vertical.
One problem is extending a straightened line, that doesn’t work. I hope that’s probably easy to fix.
You’re welcome!
I don’t think a cleaner line is possible with the types of UV meshes we’ll get from PolySrfs. There may not even be a rational edge loop coincident with the symmetry plane defined. If the mesh were a clean quad layout, I bet we’d get what you’re after with how it works now. I’ll need to investigate more but I understand what you’re saying. Many of these updates were designed to be usable on uneven UV mesh densities typical of NURBS models.
I have not used that app but this specific feature was a request from users in the footwear industry that needed to match 2D ‘upper’ graphics that were already drawn.
We’ve got some open requests for more in this area (RH-80637, RH-73997, RH-80141). I’m hoping we can add a radius of influence to vertex pin constraints. That way you could add a pin and edit that with a falloff of smoothing. FYI @Jussi_Aaltonen
You have to use constraints either to straighten a selection of edges or by adding at least two pins and align those to planar via the Gumball and scale handles. This will make that edge planar but reunwrap the adjacent polygons so they don’t overlap as a result of the change.
I’d need more specifics to know what you found and want more info about if not what you mentioned below.
Thanks, filed this as a request https://mcneel.myjetbrains.com/youtrack/issue/RH-85992 .
Thank you Brian for the details.
Here an example like horizontal/vertical fixing works in Unfold3D. In Unfold3D I can choose between pining points and horizontal/vertical mesh edges.
state after first unfold
state after adding constrains
Sometimes I add straight cuts to my NURBS model and join them again. This gives me straight mesh lines after meshing and I can use them for constraints.
I thought the edge-to-curve wasn’t visible in the video, but I just missed it. That’s fine. But the two available methods could be explained.
Example, here I have aligned two edges of this mesh (seat cushion) straight in Rhino. It would be practical if they were both horizontal and the mesh was optimally relaxed. The mesh looks very deformed and I’m a bit confused as to what to do next. It would be nice, for example, if you could select the constrained edges with a double click and then manipulate them with a gumball. Does that make sense?
Another problem is that I haven’t found a way to delete certain edge constraints when I no longer need them. It looks like I can only delete all constrains at once. Is that correct?
OK, I delete all constrains, select the mesh and press re-unwrap selected. Now I would have expected a fairly evenly unrolled mesh like at the beginning but it’s crooked. If in Unfold3D in unwrap would look like this, then I would press the optimize button and a relax process would start.
But it looked better in Rhino at the beginning of my experiment. How do I at least get it back there. Where is the reset button?
No problem for me, I have my old Unfold3D and I know that it is not fair to compare a tool that has been developed over years with the one in Rhino. I’m just trying to show what would be nice if it could be done directly in Rhino. Maybe it can still be improved.
Here one of my typical meshes for further testing.
seat cushion.obj (523.2 KB)
And here a problem. The mesh is unfolded in Unfold3D.
If I import it to Rhino it looks fine. But if I open the Rhino UV editor I can’t see the unfolded UV. Should there no be the same flat look like in Unfold3D?
#moi_unfold.obj (569.5 KB)
Hi Micha, you should see the same UV layout as you have in Unfold3d. Which version of Rhino 8 are you on?
Version 8 SR15
(8.15.25019.13001, 2025-01-19)
I checked it with a fresh started Rhino and it works.