Planar reflections in 4.14, how to set up as described in changelog?

The 4.14 changelog mentions (about the forward renderer):

How is the setup of this done? Is this just referring to the existing actor include and exclude lists, and the distance exclude? Does it just get composited in with reflection captures by the fade option, or are captures also composited in in the gaps where objects were excluded?

If I wanted to have only moveable gameplay stuff in the captures, do I have to manually add them to the actors include lists, and/or manually add the scene to the exclude lists? Is there a way to still have the scene included for shadow casting, but excluded from the rest of the capture for performance? Or do you somewhat automatically get that for stationary lighting anyway, even with the scene geometry excluded? (e.g. in a shooter game have only characters and particles and stuff in the capture, but still have them receiving shadows so when in a dark, shadowed area they aren’t improperly lit up).


The controls are somewhat limited right now. You have two choices

A) Render everything in the scene (default), with HiddenActors removed. Performance cost is usually high because the whole scene is being rendered again.
B) Specify a list of things to render through ShowOnlyActors on the PlanarReflectionComponent. There’s a corresponding blueprint function for things spawned at runtime. Nothing else will be rendered if this list is populated. Any parts of the reflection not touched by the planar reflection will fall back to reflection captures. Typically you would put gameplay components like characters in ShowOnlyActors and try to handle everything else with a BoxReflectionCapture for good performance.

There are also show flags on the planar reflection actor which allow you to turn off potentially expensive features like dynamic shadows.