The answer to this one is going to varying depending on what you’re trying to accomplish.
SceneCaptures
- “Hidden Actor” list will not draw the specified actors when drawing the scene capture to a render target
- The “Show Only Actors” rendering mode will only render the specified actors
- Recently we added a “Visible In Scene Capture Only” and “Hidden in Scene Capture” options to UPrimitiveComponent so that you don’t have to manage the Hidden Actor/ShowOnly Actor list for multiple scene capture components.
First Person Views
- Also fairly recent, we’ve added the option to specify a primitive’s “First Person Primitive Type”
- Pairing that with “Owner No See”/“Only Owner See” would enable you to have both a first- and third-person representation of the character in the same actor without having to do anything tricky to move the third person mesh “out of the way” of the first person stuff
Holdouts
- We’ve started work on a new plugin called Holdout Composite so that media players can bypass things like TSR and tonemapping and it’s available with 5.6
Linear Content/Movie Render Graph
- If you’re rendering out cinematics or anything for linear content and offline compositing, you’d use Movie Render Graph and Render Layers to mask out different primitives into different layers. My colleague Shaun Comly wrote up a great tutorial for this.
Augmented/Mixed Reality
- This one is a little trickier, and really only relevant to the AR/MR world, you can disable “Render in Main Pass” but keep 'Render in Depth Pass" enabled and it’ll treat the primitive as a kind of depth blocker, so anything rendered behind it will fail its depth test so you can make it look like something is passing behind a real-world object.
Editor-Only
- If you’ve got something like a helper icon that you want visible while editing, but not visible in the actual application you’d set “Visible” to true, and “Hidden In Game” also to true.
Does that help at all? If there are other use-cases I missed I’m happy to dig in on those.