What are considered good UVs?

gene098

Hey guys,

So Ive finished concepting,modeling and retopo
and am now up to UV stage,

(Im creating a asset for animation in UE4 game engine)

Regarding UVs I have read many articles of different individuals that say a UV should be down XYZ way. Basically everyone has a different opinion and approach...

So I decided to look at professionals who have proven results and I look at The Order 1886.

Here is their UV.



So I would like to ask, how exactly can I go about creating this type of UV?

musashidan

This type of head layout can be difficult to unwrap with minimal distortion. A lot of people now follow the VFX method of cutting as many shells as are needed to reduce the distortion to a minimum. Because texturing is done in 3D the seams don't matter as much. For games the consideration is the extra verts created by UV splits.(not a huge deal on a hero asset as in your example)

Where are you currently at in terms of unwrapping? Beginner? Complete beginner? The way you go about creating UVs like that is by knowing the fundamentals of unwrapping and applying it to whatever task you approach. There's no 'click this, do this, click that....' If you understand cutting seams, packing, relaxing, stretching, tension, etc, then you should just unwrap. If not, then you should do some study/practice/learning of the basics and apply it by experimenting.

odium

To me, a good UV depends on the assets use in-game, where its used, its scale, and what type of rendering you are using. For example if you are working on a game that's pixelated, you don't need to worry too much about padding but you will need to worry about stretching, because polygons on large angles can look quite bad. But a modern day game engine will usually smoothen out these stretched polygon UV cords, making them look a lot better... However they do introduce mip mapping, meaning that as the texture gets further away, the texture will lose resolution. This means that your UV bounds will suddenly leak into the surrounding pixels.

For me, I always give quite a large gap around every island I place, and then I make sure the texture will continue onward forever. A nice and quick way to do this is in photoshop, make all your empty space around the islands black, and then use the max filter with a radius of 1 over and over until you fill the black space. This will fill your empty space with the correct texture info, making map maps always look perfect.

Neox

@odium
Xnormal offers a padding/dilation filter for photoshop, it is pretty much what xnormal does when baking, so you can just run this instead of using maximize over and over and over again

Also, if you would straighten your UVs some more you would possibly save a ton of texturespace and pack things a little tighter. It will introduce a little more stretching but mostly in parts where it is either not visible or the new gained texture space will profit you more. Also it will make the generation of LODs a lod easier

Why those weird diagonal lines? nobody will steal your textures, and if they do, all the interesting parts are left untouched...

nomzod

Throw this onto the mesh as a base texture. Where the circles are deformed your UVs are bad. Where the letters are upside down or backwards your UVs might be bad. Where the circles are different sizes on the same shell, your UVs are definitely bad.

ONCE YOU HAVE THAT DOWN, THEN START STRETCHING THEM.

Neox

hmmmm this texture solves a few issues, it has bigger squares for far distance checkup but the contrast is kinda lacking between those. It has circles, which is great - chircles are easier to read for the human brain than squares, but those feel a bit too contrasty, if you unwrap a lot i would suggest using an overall less contrasting picture. But the biggest thing i miss here, is a fine 1px grid, that will help you check the texture density better.

I once created a checker specifically for this issue, maybe i should make an updated version one day that is meant for bigger texture resolutions. right now it is 512x512 and should solve all the issues stated above and is easier on the eye. If you want to check 1024x1024 set the tiling to 2x2, 2k would be 4x4 and 4k would be 8x8

nomzod

Oh! If you're using Maya 2016, they brought unfold3d in as a plugin. It's an incredibly robust unwrapping algorithm, I was using the standalone program for years, and the past couple of months have been a dream.

odium

Neox said:

@odium
Why those weird diagonal lines? nobody will steal your textures, and if they do, all the interesting parts are left untouched...

Those lines? The texture in the middle is without any edge padding for an example, the texture around it is the texture as it actually is. I wouldn't release something with no edge padding.

Neox

I see, what are the dots on the part without edge padding then? looks funky

odium

Neox said:

I see, what are the dots on the part without edge padding then? looks funky

Yeah I did a quick and dirty wire frame render to texture, wasn't even at full resolution.

JohnnyRaptor

Good tips, another way to get comfortable is not to commit to your first unwrap straight away when your starting up/learning.

Unwrap your asset and do a quick bake and examine the results. Find the normal seams, resolution drops etc. Take it in to your app and draw some random art on it to test out consistency. This way you can see what kind of problems bad uvs cause further down the line.

It might take a bit longer when your getting started and just itching to get to the next phase, but you will learn some valuable lessons by practice rather than just reading whats best, and as you try a few different uv layouts, your uv skills are improving as well

Eric Chadwick

We have more good tips here, along with more checker maps (and why certain maps work better than others)
http://wiki.polycount.com/wiki/Texture_Coordinates

gene098

Thanks alot guys really helpful!


Btw Im sorry for not stating it before but I am using UE4 to render this as a short film cinematic. So Im looking to make all the characters at this resolution.

_____________________________

I am a complete beginner to UV wrapping and taking each step of the character making process one step at a time.

The modeling was a lot easier for me as Im a designer and illustrator so the 3d sculpting felt familiar.

But the Retopo and UV and techincal aspects slow me down quite a bit.

_______________________________

My Plan Of Action

Im going to start by learning the fundamentals of UV from this video
https://www.youtube.com/watch?v=Ij3DafX02E8

Then Ill test out the UV by using @nomzod 's texture.
(Btw how do I set up the texture again?)

Ill also use the Unfold3d tool Ive heard and seen great things from it

And finally @JohnnyRaptor I will follow the advice given
and do quick normal bakes and test by drawing quick art on it.
(How do I do quick art?
My original idea was to use Substance Painter, but what maps do I need to make to do quick art and what programs can make them?)
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Ive seen the 1024x1024 and heard about things like 4k textures and stuff.

If Im looking for realistic skin like The Order 1886 and Uncharted 4 (Both of which are rendered with real time game engines)

Then would I be making the UV chart 4k or would the 4k be done in the texturing program? (Like Mari and Substance Painter)

Neox

your UVs usually sit in a space between 0 and 1 and are not bound to pixels, well they can be for compression reasons but thats a different story. 
So if you want to use a 4k texture you will need to tell your texturing tool.

what do you mean by quick art?

gene098

Neox said:

your UVs usually sit in a space between 0 and 1 and are not bound to pixels, well they can be for compression reasons but thats a different story. 
So if you want to use a 4k texture you will need to tell your texturing tool.

what do you mean by quick art?

Oh okay, I thought when you said the 512 and 1024 things you were talking about the UV box that goes from 0-1

Now I see that you mean that your texture can act as a scale for different texture resolutions by setting different tiling.
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Quick art was just a reference to what JohnnyRaptor said about just doing random quick art on the maps to see how it would look like on the rendered model so I dont do too much work and then waste it all.

gene098

Btw if I was to rig and find out that the eyelids need more poly edge loops,
and I already did the UV mapping

Can I go in and add some edge loops without affecting the UV map?

gene098

Hey guys

Could you draw in quick lines of where you think
on the model the above example from Order 1886's UV picture
would place their UV cuts?

Heres a picture with multiple views you guys can draw on.

musashidan

gene098 said:

Btw if I was to rig and find out that the eyelids need more poly edge loops,
and I already did the UV mapping

Can I go in and add some edge loops without affecting the UV map?

It will affect your baked tangent space normal map. The data in the texture is encoded to the verts so if you add topology the data will break. You would have to rebake.

The seams on the Order unwrap you can tell from looking at the UVs: seam from top of head to end of neck at the back/eyebags/mouthbag/nostril holes/ears.

The video you've linked yourself pretty much has the same layout.

JohnnyRaptor

The textures that nomzod and neox posted are meant to highlight any squash/stretch uv problems you might have, but i think its useful to make the mistake and see the results before trying to avoid it so you understand why you are avoiding it. 

With some random art i meant just draw some lines, use an airbrush, or alpha stamps or use a random stencil over the surface and around areas that you are suspicious about when you unwrapped. Most 3d painting apps support most of that stuff so should be quick.