Combining a terrain procedural texture node with AO illumination node and playing a bit
with the settings, I was able to get a shader compound that gives a “dirty AO look” on a geometry.
It is preferable for the geometry to already have UV coordinates, but the compound can work
nicely on a non UV mapped object too.
You can take a look at the compound’s tree and also 2 samples of its usage, on a UV mapped
(house) and a non UV mapped geometry (hoplite character), below.
You can download the compound in the Freebies section.