Texture baking help

[evanerichards]

So I am working on this project. It is a nighttime cityscape and has tons of textures, lights, etc. It is extremely heavy and takes a long time to render. Even on our render farm it takes about 20 minutes a frame. It is also a 7 second render and we can't really afford to spend 50 hours rendering.

However, there is nothing moving in the scene except for the camera. Now correct me if I am wrong, but this seems like an ideal candidate for texture baking, no?
I know very little about texture baking but I think it could really save us on this render.

So what I'd like to know is, how is this accomplished? I see the bake options in the lighting/shading menu and the baking options in the vray common tab. Are these both used? And once I bake my textures in...Do I need the entire scene evenly lit so as to light up the textures that have been baked in? Or do I need to render the baked scene out in mental ray as I see that it has created a lambert material with the baked texture in the incandescence slot?

I'm confused about this and would appreciate any advice you might be able to give.

Thanks!

[Morbid Angel]

well I got bad news and bad news for you To bake complex scene is really impractical. That is it will take much longer to bake everything properly, then to just render it out. With that said, you also cannot bake reflections. So even if you end up baking illumination, that is gi/lighting/textures you would still have to compute specular/reflection and of course if you have a case where there is strong reflection, which create reflective bounce of lighting, that will be removed in the bake.

However if I had to bake something for example 3 boxes with different uvs/shaders/textures, how I would approach this would be to combine them into one mesh and create a second uv set, where all uvs are layered out in one or few uv tiles where you can bake from your first set of maps/lighting/gi etc to the second uv set, and then just apply a vray light material to all the objects getting that baked info back on them. One thing you can do is actually make render elements, so how you would composite them in a 2d package, for example raw lighting, raw gi, diffuse and so on, then reconstruct them back in maya the same exact way via layered texture, from there you can create vray extra texture passes, and plug each one of them into corresponding pass thus creating the same output as if you really rendered a scene. One thing you need to do is to add your reflection back on to your baked geometry, this can be just a vray blend over your vray light material, the tricky thing would be getting the blending info of the reflection for each different object...which can also be time consuming.

[vlado]

Also, baking to Ptex might simplify the process a bit by removing the need to make good UV layouts...

Best regards,
Vlado