Oh, I didn’t know UE4 already has that. I was talking about that custom code, yeah. What would be the best example to look at for UE4’s Sphere_AO ?
When I checked Showdown scene, all I saw was a sphere mesh with black on white image (blob shadow image) attached to the robot and massive network of noodles in the material editor 
There are some custom UV maps involved too. Not quite sure why.