Let’s say I have a character wearing leather pants and armour.
Would I need to layout UV’s in 1 UV tile per material? 1 for skin, 1 for leather, 1 for metal armour.
Or does it not matter? Can I just cram in everything in 1 UV tile?
Also, what’s the point of UDIMS? I saw some youtube videos but still trying to wrap my head around it.
You can do whatever you want.
One UV tile per material or one for all. Depends on your demand for texture resolution.
UDIM’s are just multiple UV tiles all wrapped up into one material and fed with a series of textures.
UDIM = U-dimension.
You can fill 5 UV tiles or 50 if you wish to. These are numbered, your usual UV space is the one in the center and has the number 1001. You can move to the right and to the top following that naming convention 1002, 1003 (right) and 1011, 1021 (upwards).
The point is high texture resolutions for hero objects that get very close to the camera and better organization of materials.
It is a matter of what is the object, what is required of the UV ( how detailed ), and what you want the end result to be…
There is no right or wrong answer…You can include everything into a single UV map and be good to go, this is mostly done on Game Models, or Low-Poly models, where all the parts are made up of just low-resolution image files ( 1k ). This is fine for a background model or low-poly NPR-type work… but the main problem with this is if you wish to have details on a certain part Belt buckle or Eyes for example, then it would be required that those parts take up a larger space in the UV tile than others thereby reducing the quality of the other parts…or forcing the Material to be on a higher resolution, IE: you can get more detail on a 4k image than a 2k image…
This is where UDIMs come in, they allow you to use 2k textures and add details to those parts that need them and less detail on those that don’t each on a different UV tile, you could have all the body textures on a single tile, and then have an engraved belt buckle and belt on another…
Thanks for the explanation. Regarding the belt buckle example you gave me, is it bad to have everything on a 4K texture UV set as opposed to two 2K texture UDIM UV set?
No, it isn’t BAD but may be a waste of resources if not really needed…remember if you have a single UV map with everything on it, it is still the same UV as on a 1K, 2K, 4K, etc. The UV doesn’t change only the resolution and you get the quality on the belt buckle, but you are wasting it on a shirt that is just a Diffuse color and perhaps a Normal, those don’t need 4k for instance… but if they were on a 2k UDIM where the buckle can get its details but your not wasting resources on a diffuse texture…
Don’t forget that there is nothing that says you have to place things on a single UV, each object or set could have its own UV and 1k textures and possibly reduce cost that way…especially if image packing is used so you have a diffuse color and a roughness in 1 texture…there are many possibilities…
Then there are considerations on the model used…is it to be animated ( character walking and talking) or just for a render…
Cost doesn’t really matter on a rendered image, compared to an animated character…