Best techniques for packing UV’s

VisceralD

So just curious if the community knows of a good automatic way to pack UV. Essentially a program that you guys think does it best. Here is a few programs I tried and my ranking of it from 1-10.

1. 3ds max: 7.5, I think this is the best results I have gotten
2. Maya: 7, sometimes better then 3ds max, but sometimes it just puts the smaller pieces on top, and not between the larger pieces
3. Zbrush: UV master plugin: 5 It does a great job relaxing the UV’s but, does not do the best job laying it out
4. UV roadkill: 4, it can do a great job for low poly stuff, but is terrible on more complex stuff.

Revel

Personally I don't believe with the word "automatic" to give a good result to pack a UVs.
I just like to design my UV layout manually, it gives me total control of how it looks like. But sure to begin with the manual edit it need to auto flatten it and it start from there; stitching/ moving/ etc.

Mainly I'm using Max and modo to work and had no major problem whatsoever with both of them. Max have a great TexTools that still does the job done and modo with the combination of atlas+relax mapping/ Uber Pelt script/ Eterea UVTools.

ZBrush UVMaster I just cant get it to work quite right for me, probably because of the lack of traditional stitch/ move/ etc feature.

EarthQuake

Yeah, when it comes to uv packing, you can have good, or you can have automatic, but not both. I've yet see see an auto pack algorithm that can fill complex shapes the way I can manually. Plus, I like to group similar objects in the same area, auto packs have the tendency to scatter everything.

Bek

Some tips for manual packing:

• Start by unwrapping all your pieces, sorting out your seams and equalising texel density.
• Quickly arrange your biggest pieces to see what texture ratio is going to work best. If you've got a lot of long, thin pieces that you want to keep continuous, for a sword perhaps, then you might find 4:1 works best.
• Straighten as much as possible to prevent aliasing—although check in the viewport to see how distorted your results are.
• Try and keep islands that will be using the same material close to each other; you may not need as much padding then (plus it's slightly easier to work with when texturing)
• Remember that when you mirror something you'll also need to make sure it gets the same triangulation as its symmetrical counterpart.

oglu

headus uvlayout for everything...

Deadly Nightshade

Like EarthQuake says you have to pick between a good and an automatic UV-layout. And like EQ I haven't seen any good algorithms either.

So it comes down to doing these things manually if you want a great/packed UV layout. That manual step can be less tedious though with proper tools, such as TexTools for 3d studio Max (by Renderhjs) or Nightshade UV Editor for Maya (by myself).

Headus UV - never tried that. But it costs you money - which neither of the above alternatives do. I also recommend Roadkill for the actual unwrapping. Other than that, go with the guidelines Bek wrote down here above.

WarrenM

I stand by my opinion that automatic will never beat manual packing. It just doesn't have the knowledge that you do.

Even Headus, as awesome as it is.

I tend to take all my islands, move them off to the side, and then start moving them back in, starting from the largest ones and working my way down to the smaller ones to fill in gaps.

Noors

Packing algo are strangely pretty poor actually, but, with a way to tag clusters to sort everything the way you'd want to, i'm pretty sure an automatic packing could make "good enough" result.
Also, i couldn't/wouldn't pack manually uv's for lightmaps on a whole scene.
I'm using max. I think unfold3d pack is great too. Glad they've been chosen by autodesk.

WarrenM

That's something Headus does really well that I wish others would copy. Well, 2 things ... there's a 1 click method of straightening something into a rectangular unwrap (awesome for pipes and other things), and you can group islands together so it will keep them together when it auto packs. Super useful...

kary

Not sure when they added it, but you can group in Max now (bottom right, possibly covered by the default UI's height).

The auto pack itself is still poor, but it is handy when you are normalizing UVs across sections w/ radically different UV scales.

VisceralD

Hey guys thanks for the awesome feedback. Bek I found your suggestions very useful. Also I think Ill give headus another try.

Bartalon

I've noticed everyone seems to have their own unique, although similar, way of approaching UV mapping. I use Maya to unwrap. Here are my steps:

• Planar project each part that I want to be a UV shell
• Cut the appropriate seams to allow them to lay out flat.
• Unfold shell; repeat until all shells are flattened
• Layout command will automatically unify texel density across all shells. There are some uncommon instances where some shells will not unify properly so I do a quick check (non-frozen transformations can also affect shell resolution)
• Move shells into place given best judgment

Clark Coots

my workflow is pretty much the same as Bartalon.

after I do the auto layout so all shells have same pixel density I re-pack them manually in as small of UV space as I can. For instance instead of using full 0-1 space, I'll use 0-approx 0.85 UV space depending on the model. Then once I'm happy I'll scale everything up to fit the full 0-1 UV space. I find this process gratifying because the last step when you scale it all up you then realize how much UV space was wasted by the automatic layout.

Wozner

By the way, how to make the same textel density in 3ds max? Maya has layout command, but what about 3ds max?

Kbrom12

Wozner wrote: »

By the way, how to make the same textel density in 3ds max? Maya has layout command, but what about 3ds max?

There's a button called rescale elements, outlined it in red

Wozner

Thanks Kbrom12

This is strange, somehow when I select my UV islands and press that button it do nothing.

kary

Wozner wrote: »

Thanks Kbrom12

This is strange, somehow when I select my UV islands and press that button it do nothing.

Might not work if you have multiple objects selected w/in one UVedit modifier.

Ashaman73

perna wrote: »

Exactly. A computer can give you mathematically perfect packing, but it won't take into account all the things that are easily human-understood, like compromises, and the purpose and importance of each island. An automatic packer also doesn't know when to actually modify the island itself to fit better in the packing.

Even a mathematically perfect packing is not possible for more than the most basic and trivial problem, if you don't like to wait for several 100 years on the processing !

From a technically point of view automatic UV packing is a very hard problem (NP-hard, very similar to bin packing), where no algorithm exists, which would be able to push out a 100% solution in time.

Thane-

Wozner wrote: »

Thanks Kbrom12

This is strange, somehow when I select my UV islands and press that button it do nothing.

Please correct me if i am wrong, but *I think* that doesn't work very well if your not selecting a single object's UVs. Tex-tools's (uv plugin) normalize function does nothing when multiple objects are selected.