UV Workflow (Games) - A couple of notes

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I'm using 16.5 and currently experimenting a bit with the UV workflow.

Our low meshes at work have specific requirements regarding hard edges and UV cuts for proper normal map bakes. A couple of things that I miss right away coming from max/maya are the ability to see hard/soft edges more easily and being able to automatically cut the UVs based on hard edges.

Something like what maya does to show hard edges (right side) is what I'm looking for.
I tried creating a custom viewport visualizer but could not achieve it, maybe it's possible?
Now that I mention this, I would also like to be able to see the UV seams in the mesh, in the 3D viewport.




It would also be nice if the UV Unwrap node had a toggle to automatically cut the UVs based on hard edges. I set an edge as a hard edge on purpose, however the UV Unwrap keeps it together because of the angle I suppose.



Same issue the other way around, I have a round-ish strip of polygons that are all soft because I want it that way, however the UV Unwrap node places unwanted seams.



So yep, it would be nice to have some extra control over this stuff.


Lastly, -and especially this might be due to my limited knowledge- manually welding UV islands is not as straight forward as I expected.

I tried selecting the 2 edges that I wanted to weld and used an UV Fuse node, but nothing really happened.
So then I tried manually welding vertex by vertex using UV Fuse nodes. That worked but it's just not practical.
On top of that, I could not find a way to relax these welded islands. Using the UV Layout node again fixed the overlaping, but not the distortion.




There are more things that I will talk about once I experiment a bit more… I'm not trying to make houdini work like max/maya, but some things are just really handy to have, at least for our workflow here.

Cheers
Edited by LittleNinja - Nov. 13, 2017 10:50:54
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For showing hard 3D edges and UV boundaries, what you're looking for is the boundary display in the Display Options.



Note that it does take extra time to compute if visible, so you may not want it on by default.
Edited by malexander - Nov. 13, 2017 11:00:58

Attachments:
display-opts.png (90.4 KB)

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Oh nice thanks, I completely overlooked that one. That needs to be moved to the display options bar in the viewport!

I don't see an option to see the hard edges as in non-smoothed normals though. For simple models like the one I'm using now to test it's not a big deal, but for more complex meshes it can be pretty helpful.

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The 3D boundaries are based on P, while the UV boundaries are based on uv. There's no boundary options for other attributes, such as N.
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Here is a scene file showing how to use edge groups and uvflatten to get the results that I think you are looking for. (please excuse the sloppy model - I just wanted to get something similar to what you were showing)
Edited by rmagee - Nov. 13, 2017 17:23:09

Attachments:
uv_flatten_example.hip (83.7 KB)
uvflatten.jpg (349.8 KB)

Robert Magee
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Thanks for the example. I see that actually gives you quite a lot of control.
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