When 3D painting, are automatic UV unwraps acceptable?

DDevilfish

Hey everybody, I'm back with a question regarding UV unwrapping in certain situations. I've seen countless tutorials on how to unwrap, and I'm not having trouble with that specifically... but when using a 3d painting program like mudbox for texturing, is it okay to skip the more painful parts of unwrapping and just use the auto unwrap? Obviously it will physically work, but the textures will be an unholy mess to look at for complicated objects. I have seen only one rather advanced, current gen tutorial where his unwrap seemed to have been automatic, and he just navigated the mess when working by hand in photoshop, for example. There is a lot more material out there that looks more hand-tweaked and organized, but it's also frequently several years old.

If I was working in the game industry, and produced an otherwise beautiful asset but the texture sheets are incomprehensible due to auto-unwrap and packing... would that be a bad thing? Or is that "the new normal" for current gen stuff that isn't hand-painted? Thanks.

Synaesthesia

I'm sure it's feasible to rush through UVs, but I wouldn't do it - not professionally or personally. Properly created UVs are always easier to work with and always produce a better texture. It's worth the tradeoff in time. In fact, I'd wager it's probably better to do it right to begin with - at least you won't need to worry about potentially redoing your entire texture work because you rushed through a critical phase of development.

Ruz

well I prefer to have proper uv's , tiles and such are a short term solution

PolyHertz

If you're still messing with the topology on a really lowpoly mesh, and just want to see if the way you've modeled something will work out, then go for it. But the final piece should always have proper UV's.

gnoop

Well. I am still doing textures in Zbrush sometimes with auto PUVTunwrap  exporting twice of target resolution  and sometimes with my set of procedural "dirt" and "curvature"  shaders extra to Zbrush paint   (in 3d soft  where UV's are irrelevant).     Then I just bake it  to target low poly .

Done it  years  before  Substance,  Mari or DDO appeared  and sometimes it still seems to me as most simple and easy to tweak, re-use and setup way.   

DDevilfish

Seems pretty clear to me that everyone still works toward a final product with sensible hand-organized UVs, and the tutorial I'm referring to was a bit of an outlier. Thanks for the answers

SnowInChina

are you having troubles with unwrapping, or do you simply want to save the time to do a proper unwrap.
i am asking because i have seen a lot of people who have problems wrapping their head around uvs

oglu

depends on the project and the asset... i do clean uvs for all hero assets but background objects get automatic uvs... i you get only one day to create an asset dont waste time on uvs... 

but again depends on the client, time, if the object is animated, close to the camera, needs handpainted textures, will be reused later, does go into a game engine or is for offline render.....

DDevilfish

Thanks for asking SnowinChina. I've gotten pretty good at unwrapping, I think, so no problems there. I tend to come around with these questions about workflow and what is acceptable, from time to time... mainly because I've been self-teaching and I'm concerned about building bad habits. Right now I'm trying to fill out an entry level portfolio, so it really gets me thinking about how to do things "right". I feel like there are a lot of hacks and shortcuts one can take in 3d and still get a good end result, but without more experience I can't judge which ones are going to bite me in the butt later.

This one... not having to mess with UVs at all... sounds lovely but too good to be true, so I had to ask.

Also thanks Oglu, you've responded to like 3 of my questions now, appreciate it.

Aabel

If you want to texture first, UV later you could use a texturing program that supports Ptex, and bake to UV later. As far as I know Mari is the only texturing software that supports that particular workflow off the shelf.

PolyHertz

Aabel said:

Ptex...As far as I know Mari is the only texturing software that supports that particular workflow off the shelf.

3D-Coat and Mudbox also support Ptex.

Aabel

Yes, they support authoring in Ptex, what I am unsure of is if they support baking from Ptex to UV

melviso

I wish Blender could get Ptex support too. But what I am thinking would have been even better is a resolution independent file format that looks like raster. I don't know why there hasn't been one made or  is research going on in this area? There is vector which is resolution independent but has a certain look to it  though and I think the file size is higher than raster? I am not sure if renderers currently support vector as maps, only raster currently.
So with a simple uv or automatic uv set up, the resolution is the same.
The problem with ptex is texturing say brick on a curved surface would be a problem unless you convert to uv flattened mesh in some softwares so the need for a proper uv set up is still there.

oglu

there is no real ptex painter out there... all of them need uvs in the background... only disney and blizzard have a painting solution painting direct to ptex...

poopipe

In production you would be expected to provide LODs that all share the same texture sheet.

So no,  an auto unwrap probably wont be enough 

Linko

Personally I never do retopology and UV mapping because you can get great result with decimation and Smart UVs project for static game assets, like you can see in this demo: https://youtu.be/-Fy7g3g6uCI

For the texel density a new auto-packing algorithm is in preparation in the Blender source code, for now it's an addon: https://gumroad.com/l/UVShotPacker

The technique is to start with a fake hand painted base then to finish your texture in 3D paint so problems like bad seams placement and brush strokes bleeding will be less noticeable.

To fake hand painting you need to have an high poly that will create your hand painted details and to bake a normal map on your generated UVs (and generated low poly with decimation + bool tool union) and to use diffuse colors to do your ID masks. To save time on the microdetails I use procedural texture project in Object coordinate with a low blend then I connect it to the displacement shader.

Then you convert the normal map into a a curvature and curvature smooth maps in Substance Designer or in Blender
Curvature map: https://blender.stackexchange.com/a/72602/23134
Smooth curvature: https://blender.stackexchange.com/a/100637/23134
Fake hand painting by using color ramps and analogous colors or do that in Photoshop: https://blender.stackexchange.com/a/90153/23134

Then you can open your model with the fake hand painted texture and add a layer in overlay or mix mode and 3D paint it for the subtle touches, then composite your two textures to get your final texture.

Note about the Smart UVs of Blender: use an angle of 45 instead of 66 to avoid overlapping on organic shapes.

Note 2: all this process can be automated with the free Blender addon AssetGen.

melviso

oglu said:

there is no real ptex painter out there... all of them need uvs in the background... only disney and blizzard have a painting solution painting direct to ptex...

Really? Is there a reason why this isn't available to the public. I thought Mari  had something like this.

What I am wishing for is renderers and games supporting vector maps that are resolution independent. Uvs are important. If textures are resolution independent, uvs and their placements would not matter much.

Hoping 3d painting softwares support painting vector maps the way raster is currently supported.

Burpee

oglu said:

there is no real ptex painter out there... all of them need uvs in the background... only disney and blizzard have a painting solution painting direct to ptex...

I'd be curious to have more details on that !

Eric Chadwick

http://polycount.com/discussion/138265/how-do-animation-studios-texture

oglu

they told me its easier to use the existing uv based tech and bake to ptex during export... they create uvs for each face and many udims in the background... in the end you get a ptex file... but with really high resolution a ptex file gets huge...

its also not supported by all graphic card driver to work with real ptex... and there arnt many ptex users... for example arnold cant render ptex... so all arnold based studios wont use it... its also hard to reuse ptex files.. its easy to break ptex... to less demand to develop the real thing...

and its tricky to mipmap ptex... its bound to the faces of the object... for each LOD you need a new ptex file...

the only renderer that handels ptex like it should be is renderman... all other are limited in some kind...

Burpee

interesting, thanks !