Unwrap dilemma, hairs too much UV, face not enough UV

Tiles

Hello everybody,

I have a game character with a mapping dilemma here. My face area for the character just gets a few texels from the texture. The texture wouldn't be a this big problem, but the normalmap has also just a few pixels there then. And this doesn't make me a happy bunny.

It is not the first time that i have not enough space left for the UV patch for the face area. So i guess it's time to ask the experts here. How would you solve it? Where am i wrong?

From the unwrap you can guess that one of my main problems in this special case is the hair. I want just to have one map when possible. My character needs some hair though. So i modeled them polygonal, directly on top of the head. And this eats lots of space in the unwrap. At least at the moment. The UV patches do not overlap. That way i can clean the seams. But it is really lots of UV space just for the hairs.

How would you guys solve the problem? Remove the hair as it is now? And make the hairs extra by planes? What about the face area? How can i make and map such a character here with hair in the best way?

Eric Chadwick

Hair usually uses a separate bitmap, for two reasons:

1. alpha blend renders more slowly so you limit it to just the parts that need it
2. when you add an alpha channel to a large texture it greatly increases the file size in memory, so it's better to add an alpha channel to a smaller hair-only texture, thereby increasing memory use much less.

Also with polygonal hair it's usually best to reuse UVs. You really only need 3 or 4 hair pieces, duplicated and bent all over the head.

As for the face, it depends on the use of the character. Will the face be seen in closeup? If so the face can use more texture space than the body. Or will the character always be seen full-figure, in the distance? If so then you'll want an even pixel density across the model.

Tiles

Thanks Eric

I have for now removed the hair from the character again. And will do as suggested. I will make the hair extra by some polygonal strips now.

My dilemma with the face is that i want both. As much detail in closeup as possible, and a averall look with not too much differences in the texel size. Means the texel size of the face area shouldn't differ too much from the rest of the character. I think i will use a size of 1.5x or 2x for the face area compared to the rest of the character. And simply have a look how it turns out.

I'll show the updated progress when i'm done with that. I may need a few days though

Eric Chadwick

We have a page on the wiki about hair look for HairTechnique.

If you want, you can divide the head into its own unique texture, so you can use a bigger texture for the head alone.

Also you can overlap symmetrical parts of the body to save UV space

Tiles

Tanks Eric, that's indeed a great resource. Already investigating there

I want to avoid to divide the head into a separate texture to save drawcalls. There are already the eyes and the teeth at separate textures. Now the hair too. The body is unfortunately not really symmetric. The only body parts that are symmetric are hands and feet. Which is not this much to save that it could be worth it. But separating the hairs has already freed quite a few space. So i think i am at a good way now.

Tiles

Intermediate update. Hairs removed. And the face area has a scaling of 1.5 now compared to the rest. Gives me enough space for the face, but isn't this brutal different in texels that you will notice it immediately.

Now i'm a happy bunny. Thanks for help

Eric Chadwick

Yay! Much better UV layout, good job.