Reflection probes are lovely and nice when set up with tremendous precision, but getting them to work inside any building more interesting than a rectangular prism is a difficult usability problem. To see the effect the probes are having, we need them invisible, and of course it's very hard to precisely adjust the edges of invisible things. But when we turn on probe highlighting, the whole interior of buildings goes overlapping shades of yellow, making it imposible to see how the probes are affecting the lighting.

Or, basically: Setting probes up is insanely finicky, and just not a good user experience.

Suggested solution: "Fill with Probes." Some kind of Build Menu tool that very simply tries a one-time task of using one or more box-shapes, scaled and rotated, opverlapping, to fill in the area inside the selected object. This combination shape is then set as probes.

Basically, instead of the builder trying to manually rotate and stretch edges of probes onto mesh in an editing environment that has no mesh snapping, a viewer-based took that knows where the nearest edges of the mesh are located can do it for us.