AO2 uses a second occlusion map, usually mapped to UV1, to provide ambient occlusion on the scale of a lightmap.
NOTE: Unlike a lightmap, this AO map will contribute to our dynamically generated specular occlusion.
This feature is aimed at the arch-viz folks who need more dynamic ambient lighting, but still want some of the baked detail of a lightmap. It's especially useful in contexts where environment geometry is textured using shared/tiling textures, but you still wish to use baked ambient occlusion for the entirety of a construct. In this situation, you can simply bake your per-object/scene AO using the 2nd UV set for your meshes, and set the mode in this property group to UV1.
|AO2(G)||Color Map||(G) Occlusion Map. [Tiling, Offset, UV Set]|
|Occlusion Strength||Float [0-1]||The intensity of the ambient occlusion.|