An artist would need to put such greyscale ambient textures on a model:
An then put actual textures on it.
In GMT files used by rFactor, each texture has it's own mapping (own UV set) and I think it's obvious that you need to use different UV for main texture and for ambient map.
Unfortunately, neither 3D studio nor Blender, nor 3Dsimed can do that (even if rFactor can).
On some smaller objects you can just darken main texture near corners and under roofs. It's far from perfect, but still better than entirely flat shading of interiors.
This is how it's done with cars - ambient occlusion is added to car's texture.
No.But in saying that I just realised, isn't this what a bump map can do and have it be dynamic?
Amount of ambient light received by given object is controlled by "proximity of other objects" that may cover the main source of ambient light - the sky.
So it's not about having some texture on an object, it's about knowing where other objects are. So no texture tricks will give you dynamic ambient occlusion or anything near it.
Only static ambient occlusion can be done using textures, because if objects do not move, artist will know which parts will be darker.