Lighting & Lumen

UE5's default lighting pipeline is fully dynamic: Lumen provides global illumination (GI) and reflections without a bake. Understanding the light component hierarchy, mobility rules, and the Lumen/post-process stack lets you get correct and performant results quickly.

When to use this skill

• Creating or modifying a light component in C++ (type selection, intensity/color/units, attenuation, IES profiles, light functions).
• Choosing the right mobility for a light and understanding the GI/shadow consequences.
• Enabling, tuning, or debugging Lumen GI and Lumen Reflections.
• Setting up sky atmosphere, sky light, volumetric clouds, and exponential height fog.
• Configuring post process volumes for exposure, auto-exposure, bloom, color grading, or per-area Lumen overrides.
• Placing reflection captures for areas Lumen cannot reach (legacy or spec-heavy interiors).
• Deciding when to use baked Lightmass vs Lumen.