Global Illumination baking

carljogen

Hello,

This should be pretty obvious to quite a few of you but how do you bake global illumination to textures? I'm coming from VFX so some of the game workflows are alien to me.

I was thinking baking GI to second UV map in the same way that you bake the shadow map. To make it clear, at the end of the baking process I'd have two maps.

1 shadow map
1 GI

So in summary: final color texture = (Diffuse Map + GI Map)* Shadow map. Is this the correct workflow or is there something I'm missing.

Also one thing that I'm not sure about is, I can get away with using very low resolution shadow maps but I'm guessing I won't be able to get away with a low resolution GI map because of the color information? Any thoughts on that?

Carl

Eric Chadwick

Depends on the game engine you're working with, and the platform you're aiming for.

Like, if it's for a mobile game, you'll just bake all lighting using the diffuse UVs and combine with the diffuse in Photoshop.

But for PC or console, the shadow map will often be calculated at runtime. The GI map should probably be masking your ambient lighting, not your diffuse.

Depends on a lot of things. How close the model is to the player, etc.

Froyok

Some games also store the GI in the vertex colors and blend it with the shadow maps in the shader at runtime (Uncharted 3 do this for example).

Eric Chadwick

We have some more info here.
http://wiki.polycount.com/AmbientOcclusionMap