I encountered a bug with caustic generation.
When you add detail to to a caustic generating surface (e.g. glass) like bump or normal maps, unfortunately the surface variations do not show up in the caustic pattern.
This this is in my opinion a severe limitation and could cause scenes to not look as realistic as they could. You can see this quite well with the unevenness of caustics refracting through a glass on a sunny day. Most glass like objekts in CG are rather perfect in their form. So adding little imperfections though bump or normals and getting those reflected in the caustics would bring a lot of realism to some scenes.
Attached are two renders. One with bump, where you would expect the uneven caustics to show up, but they do not.
Then another render using displacement to show how it should look.
