High Level Options for Lighting

Go to World Settings → Lightmass. Lightmass is the way in which all lighting calculations are done in Unreal Engine.

• Static Lighting Level Scale: The overall scale. This is set to 1. There should be no reason to change this from it’s default setting.
• Num Indirect Lighting Bounce: How many times a light ray will bounce off of surfaces.
• Indirect Lighting Quality: How accurate is the light bouncing?
• Indirect Lighting Smoothing: A value that smooths lighting errors.
• Environment Color: Adds an overall tint to the scene. Similar to sky color. A way to get a natural look is to change this to a blue/purple color. This will alter the color of shadows.
• Environment Intensity: Useful if the environment has bright bold colors. It will boost that factor.
• Diffuse Boost: Similar to the Environment Intensity feature.
• Use Ambient Occlusion: Turning on ambient occlusion globally enables a host of other features related to ambient occlusion shading.

Lightmass Importance Volume

Allows us to control the quality of lighting in various areas of the level separately from each other, assigning higher quality to some areas than others. It says “whatever is in my bounds, calculate the Lightmass settings at a higher quality.” If there are multiple lightmass importance volumes in the scene, Unreal Engine will create a new lightmass importance volume based on the boundaries of all the volumes (a boundary box for all volumes). You will not get a performance gain by using multiple lightmass volumes.