Modular Wall System UV Question

Budner

Hello. 

I’m trying to get into environment art and got a question about modular wall systems. 

I saw the breakdowns from Dishonored 2 and wondered how they made all the pieces work together in terms of the texture tilling over the walls. 

So the bigger pieces just go from a U0 to U1 in the uv space so I have no problem there. But what’s with the smaller pieces, how do you make them work.

The only thing I could think of is to add an edge in the middle of the piece and put both outer edges to U0. Then it tilles but the uv mirrors in the middle which can look really bad.

So what are some other options?

I’m working with 3ds Max and Unreal 4 btw.

Eric Chadwick

Many ways to achieve this. Search "modular" on the wiki.
http://wiki.polycount.com/w/index.php?search=modular&go=Go&title=Special:Search

One easy way, make the texture tile with itself in multiple places. Ben Mathis called this Thirding and made a quick tutorial on it.
http://wiki.polycount.com/w/index.php?search=thirding&go=Go&title=Special:Search

Butthair

I would use world aligned textures so they match up based on world space position.
UVs are generated in shader that align to object's world position
http://www.undeaddev.com/now-this-is-what-its-like-when-worlds-align/

Budner

Thank you very much. Sadly some of the wiki Links are dead. Looking through the other ones.

Would that World Align Texture method have a bigger impact on performance than a let's say a normal shader (meaning without the World Align notes)?

Eric Chadwick

Yeah unfortunately some of the forum embeds are gone; we can't control it when people let their websites die. 

World-aligned UVs are a bit more expensive, and they suffer from a few visual artifacts. 

Budner

Of course you can't control that.

Ok, good to know. Will see what works best for me.
Thank you

Mirbobo

They used 2 UV sets and vertex blending on the smaller pieces. There was a polycount post explaining it on one of the environment art dumps 
http://polycount.com/discussion/comment/2533186/#Comment_2533186

HAWK12HT

Hope this might help you, made this long long ago. Also link is not dead  

https://www.youtube.com/watch?v=Gxdjc2a7Toc

Olli.

you could also just have modular set pieces that arent fully UVed, and once you finish combining your interiors you can join the UVs.

RN

Butthair said:

I would use world aligned textures so they match up based on world space position.
UVs are generated in shader that align to object's world position
http://www.undeaddev.com/now-this-is-what-its-like-when-worlds-align/

That's brilliant. I've seen something similar to this called "triplanar mapping", using world coordinates directly as UVW coordinates:
http://www.martinpalko.com/triplanar-mapping/

Nosslak

RN said:

Butthair said:

I would use world aligned textures so they match up based on world space position.
UVs are generated in shader that align to object's world position
http://www.undeaddev.com/now-this-is-what-its-like-when-worlds-align/

That's brilliant. I've seen something similar to this called "triplanar mapping", using world coordinates directly as UVW coordinates:
http://www.martinpalko.com/triplanar-mapping/

It sounds good at first, but if you were to use any kind wallpaper with a distinct pattern (like a victorian one) or a brickwall on a surface that isn't aligned to the world-axis (like say a cylinder or a wall at a 45 degree angle) it would quickly break down. Should work well on more generic textures like concrete without any obvious patterns though.

Butthair

@Nosslak is addressing the issue with tri-planar mapping. This method is idea for rocks and other natural noise, or else for micro surface details. Which is the main benefit when your base texture can only hold so much detail at it's resolution.
Like tiling details, but this one doesn't care about object scaling, it keep it consistent through the world.

I think there's enough answers here to address OP's goal, however they are all fairly technical, requiring some extra level of shader instruction. I don't know if there is a way of approaching this kind of modularity without the use of shaders. So I'm wondering, is there a way, without using world aligned texturing, tri planar mapping, or UV blending 2 different channels (which is how they actually did it), to achieve this look?

Without shader code, I keep coming back to thinking the kit has to be redesigned, which is also not the goal.

jessnado

For something like this wallpaper  @Nosslak posted you could do a full 0-1 unwrap for your "full" wall piece then just half, and quarter it where the mirroring happens for your "half" and "quarter" wall segments. Usually modular kits work in set increments so depending on the texture this is doable. You'd then use decals, shader effects, alternate textures, or just props to minimize any obvious repetition. It gets trickier with something like brick unless you tile it by 2 so you can have a full and half wall piece.

Eric Chadwick

Yep, thirding.

Though I gotta say, for modular meshes you generally want to avoid thirds because they don't easily fit into a grid to add up to 100%. Better to use fourths...