In this section, we will briefly go through the three topics listed in the heading, which are often confusing to new or casual game makers:
- Volumetric lightmaps are a precomputed volume-based set of colors that can be quickly used to determine the bounced lighting in any given area of your map. For those who are familiar with pre-4.18 UE4, this was done via the Indirect Lighting Cache, but that was a fixed sample size. The new lightmaps use more dynamic sampling for added detail. These are different from a plain lightmap, which is color that is directly baked into a scene and applied to objects typically as a blended texture. Another way to think of volumetric lightmaps is as a quick look-up table of complex color information in samples of space.
- Lightmass is the system name in Unreal that determines your lighting properties...