This seems like such a simple thing that I had forgotten it wasn’t a feature until I attempted to create an effect using this.
Please add the ability for Scene Capture Actors to capture the Custom Depth/Stencil buffer to a single channel, possibly with an additional option to capture the standard Scene Depth to another packed channel.
And no, relying on a Post Process isn’t a suitable replacement for certain types of effects that rely on affecting the depth buffer like Pixel Depth Offset and World Position Offset. For example, I was trying to create an opaque material that would use Custom Depth to track its silhouette and then use that information to do some Pixel Depth and World Position offsets.
Because opaque materials can’t read scene textures, the idea was to use a camera aligned Scene Capture to write the Custom Depth to a texture that would be usable by an opaque material, but as far as I can tell, this is impossible simply because Scene Captures can’t capture Custom Depth/Stencil.