Combine High Poly Bake & Trimsheet ?

Elliott

Hi,

I'm learning trimsheets at the moment and I'm asking a question
that may seem a little stupid but I'm asking anyway.
Is that possible to combine high poly bake & Trimsheet ? 

When you're making a Trimsheet texture, you're making a normal map with it.
So, if you want to have a complex model (without extreme amount of polygons), you must 
bake the high poly details on the low poly mesh, but then, you have the normal map, so
it's not possible to apply a trimsheet texture anymore ? Exept with only colors on it I guess... 

I saw thoses images of props on Artstation and I'm wondering : Thoses models are suitable for trimsheet texture, 
but it seems they didn't do that because, the wood parts are very detailed and differents. Or maybe they
are using 1 map for all of thoses windows ? 



Same question for this modular set, are they using trimsheet for this ? 
Because, it seems the props are uniques sculpts or I'm not understanding the process

(link : https://www.artstation.com/artwork/obmVWq)

poopipe

They'll have made a texture atlas that combines a base set of unique and tiling elements and then built a load of meshes that are UVd to it. 

Elliott

poopipe said:

They'll have made a texture atlas that combines a base set of unique and tiling elements and then built a load of meshes that are UVd to it. 

So they don't use Trimsheet at all ?
I thought is was used more as possible in video games

Fabi_G

Building modules from a set amount of parts means their UVs are mapped to same pixels, maximizing the use of the texture - same as with mapping UVs of several parts to trims. As poopie wrote, it's fine to combine unique and tiling elements into one texture. Approach depends on the specific kit. What matters in the end is that the visual target is met within the given budget.

Alex_J

somebody could correct me if I am wrong because I dont do a ton of this sort of thing but I think it is correct to say that a trim sheet is a texture atlas, the only thing which makes it different is the intent it's used for.

So if you combine the textures of ten characters into one image, thats a texture atlas. If you combine some details which would be used to add trim details to a building into one atlas, that's a trim sheet.

if that is correct then what is shown in original image probably wouldnt involve any trim details because its not stuff like big flat walls which need a trim, it's individual relatively high detail modular pieces which you'd probably be using like ornaments to add to walls or as props.

sprunghunt

You can mix trim sheets with unique normal maps. I do it all the time. 

On all these props there is still a lot of texture re-use. If you look at the window frames they use the same wooden pieces over and over again but in different configurations. This is just another way to save on texture resolution. 

Elliott

Thank you guys for the clarifications.

sprunghunt said:

You can mix trim sheets with unique normal maps. I do it all the time. 

On all these props there is still a lot of texture re-use. If you look at the window frames they use the same wooden pieces over and over again but in different configurations. This is just another way to save on texture resolution. 

@sprunghunt, you mean using an Atlas Texture ?
Or using a unique map in normal slot and a tilleable one in the Albedo slot ?

fmorera

An Atlas texture is a file with all the textures in it. For example the albedo.
If you want to use trimsheets you just need to do the UVs over the image. Is compatible, you could do an Atlas of the trimsheets.
In that image what is reusing is the geometry (albedo, normal and everything) of a wooden plank or a log.
You can also create different UVs if you want, for example have a light map or a custom map per object.

dimwalker

fmorera said:

you could do an Atlas of the trimsheets

Doesn't that defeat the purpose of trimsheet? Mapping will break unless all UV shells can fit inside 0-1 space.

ZacD

If a trimsheet doesn't allow for wrapping outside of 0-1, it's no longer a trim sheet and just an atlas, at least in my opinion. You can use unused space on a trimsheet as an atlas though. 

pior

This thread seems to be running in circles, perhaps because of a misunderstanding of the question by the OP - and then things get even more mixed up because of terminology.

@Elliott : you seem to understand the difference between "unique" UVs (say, for a typical character) and "environment style" UVs. Why do you assume that the two can't be used at the same time ? 

For instance, top left here is a character texture from Fortnite (typical "unique" UVs) ; and top right a is an environment texture from Sunset Overdrive (typical "trim sheet" UVs). Absolutely nothing prevents you from combining both approaches within an asset, as shown on the bottom hybrid. As a matter of fact, even though it may not seem intuitive I tend to believe that this is probably the most efficient way to work on characters (as long as the Art Direction is not requiring everything to be 100% sculpted). Games like Arms and Splatoon seem to use this approach a lot.


If a production requires everything to be fancy-sculpted, then naturally things will tend to steer towards "unique UVs" because the next logical step after spending hours on a sculpt is to retopo it and bake it. But if the production requires things to be lowpoly-modeled first (for faster in-game proofing, which I personally think is way more valuable than spending hours on sculpts...), then more creative approaches to texturing can be used.

ZacD

The Ascent took a similar approach as well, 

https://youtu.be/FodXp5BkENk?t=561

Elliott

Ok, I get it now, thanks  

pior

This is cool : just had a look at a random environment asset from the game ... and it does indeed perfectly work with the master texture shown in the GDC presentation

Eric Chadwick

We have links to modular/trimsheet/atlas tutorials here, in case it helps to see more examples and walkthroughs 
http://wiki.polycount.com/wiki/Modular_environments