Right now people can sort of create a light node by creating a cube camera and then manually rendering it. I was wondering if it may be worthwhile at some point to create a light probe node type based on Object3D like UE4 has. It would contain I guess both a cube camera and an HDR cube map texture, as well as some logic for an update strategy (either once or some other frequency.)
I think that for a light probe to be truely useful, it will need something like an exclusion list — a set of objects that should not be visible when updating the light probe. This is useful for the case of a light probe situated exactly at a location of a key reflective object.
I am a bit confused on how light probes are used by materials in UE4 in the end. Does each object just look for the nearest LightProbe and use that one as its environment map or does it interpolate between the nearest few light probes? Or do you manually assign light probes to a material?
I can view manual assignment of light probes to a material as useful in the case of something like a moving car, have a light probe on the car that is located exactly where the car is.