Ambient Occlusion detects the proximity distance between objects and removes light where GI would inject light into a scene.
You can see the Distant Field GI work being done here. As Daniel notes, this is still early on.
If you want AO, add a skylight and set it to movable.
To the original matter with the edge issue at that corner. I was able to reproduce that as well, but only with BSP converted to a static mesh.
I was able to clear it up by increasing the distance field on my end.
The best result I got though was making the same shaped mesh in my modeling program (3Ds Max). The way that BSP converts to static mesh can leave odd cuts for the polygons vs being able to determine those cuts myself in a modeling program.
As Daniel mentioned in the video as well, it’s better to have more uniform kinds of models when doing this. You’ll get better results.
Here are the results I had with a BSP converted to Static Mesh:
This was just a single wall with a hold cut out that was converted.
Distance Field Resolution: 1
Distance Field Resolution: 75
Next this is one I created in 3Ds max:
Distance Field Resolution: 1
Distance Field Resolution: 6
As you can see it’s much better to use a custom made static mesh. It probably helps to that my static mesh made outside of the editor was more uniform as well.
This system still has some improvements coming as it’s being developed that should help with some of these things.
Tim