LIGHTING breakdown

Brian Leleux explains his lighting process

Mos Eisley is all baked lighting, with some dynamic shadows from the major light sources, explains Brian Leleux, lighting artist at Obsidian Entertainment: “I was not too happy with Light Projection Volumes, Distance Field GI, or Distance Field AO for this project, as they offered too little control or had too many visual artefacts at the time.”

Brian says he generally starts lighting a scene using as few post-process effects as possible, “including no bloom, colour adjustments, or any major exposure tweaks. This allows me to focus solely on the lights themselves, while still seeing the diffuse textures and the original colours of the area I’m working in.”

When lighting any scene, Brian starts with whatever the dominant light source is going to be. For exteriors this would be the sunlight and sky’s light. For interiors it’s whatever the primary light colour and shadow caster will be. “For Mos Eisley’s interiors, it was all of the standard ceiling lights,” says Brian.

“Once the primary lights are in place, I do a Medium or High build to see how everything bakes. Build times weren’t much of a concern, so I used pretty high settings. Although adjusting the Static Lighting Level Scale breaks the ‘physically correctness’ of Lightmass calculations, the results are generally better looking in terms of quality,” explains Brian.

Once completed, Brian looks at where he could potentially improve GI bounces to brighten the dark areas and increase visibility of the key ones. “When I am trying to increase bounce lighting, I like to place static lights that don’t use the physically correct Inverse Squared Falloff or cast shadows,” says Brian. “The Static light option removes all Specular contribution and the older falloff method gives me a little bit more control over the light falloff. The Specular is still picked up in cubemaps though, so the position of the lights and reflection actors can cause some problems with random specular hotspots.”

Once the area has been fleshed out, Brian incorporated the subtle features that helped ground the scene more. “Additional cubemaps, AO tweaks, colour grading, and other post-process tweaks are all made with this step,” he says.

FINAL TWEAKS The medium quality bake with the hand-placed lights, but without post-process (left). The same settings, but post-process settings enabled. depth of field, bloom, dirty lens texture, saturation and contrast tweaks (right)

MENU SETTINGS Lightmass is the system responsible for calculating indirect lighting within UE4. Check out the Lightmass settings for the final build of Mos Eisley

INCREASE COLOUR bounce lights are placed around the scene to increase the colour from some of the saturated pieces. Light Falloff for bounce lights that have Use Inverse Squared Falloff unchecked. 16 (max) on left, 0.0001 (min) on right.

LIGHTING TESTS “base lighting in the test level, using only the dominant directional Light, Sky Light and simple post-process effect,” says brian