I was going to post with a question about a problem with what appeared to be a constant ambient light that was affecting my scene, however, I managed to figure it out and thought it would be useful to add to the top post of this thread, simply because it’s a setting within Post Process Volume that is not set properly for VXGI by default.
My scene was being lit by some mystery source of flat lighting (although BSP was unaffected). After much hunting, I found that changing the “Indirect Lighting Intensity” to 0 under the Global Illumination tab of my Post Process Volume fixed the problem. It might not have been that noticeable in a scene lit by a skylight, but with a single tucked-away spotlight as my light source, it was a pretty annoying problem. Before and after shots are below:
Post Process Volume >> Global Illumination >> Indirect Lighting Intensity: 1.0 (ugly)
Post Process Volume >> Global Illumination >> Indirect Lighting Intensity: 0.0 (beautiful)
EDIT: I also realized that this could’ve been solved pretty easily by just disabling static lighting of any kind in the project settings menu. Doh.