OptionalambientOptionalexposureExposure multiplier on the light, before highlight roll-off (default 0.85).
OptionalfillStrength of the fill bouncing in from the side opposite the sun (default 0.1).
OptionalgroundHemisphere-ambient ground colour (default [0.24, 0.2, 0.17], a warm bounce).
OptionalrimRim-light strength, a fixed light from -Z (default 0.05).
OptionalskyOptional explicit sky gradient for the sky pass. When omitted, a palette is derived from the sun's altitude (day → golden hour → twilight → night).
OptionalskyHemisphere-ambient sky colour (default [0.34, 0.35, 0.36]). Kept close to neutral: the ambient carries almost half of the key light, so a strongly blue sky would tint every sunlit white surface.
OptionalskyDraw the procedural sky background. When false (default) the frame
clears to RenderOptions.clearColor exactly as before.
OptionalsunOptionalsunUnit vector toward the sun (Y-up viewer space). Normalized defensively.
OptionalsunDiffuse strength of the one-sided sun term (default 0.4).
OptionalsunSun terminator softness — the diffuse "wrap" that lifts the light/shadow
boundary off a hard max(N·L, 0) toward wrap-around lighting. 0 is a crisp
terminator (hard shadows); larger values soften it (overcast look). Default
0.3. Clamped to [0, 1] on resolve.
Hemisphere ambient strength (default 0.775). This is what lights faces turned away from the sun, so it sets how dark the shaded side and cast shadows read.