What is the difference between Mixed Lighting and Real-time Global Illumination, and when would you use each?

• A. Mixed Lighting bakes static lighting and uses real-time shadows for dynamic objects; Real-time GI updates lighting continuously for highly dynamic geometry.
• B. Mixed Lighting uses only baked data; Real-time GI uses only real-time shadows.
• C. Mixed Lighting uses dynamic reflections; Real-time GI uses static reflections.
• D. Mixed Lighting is deprecated; Real-time GI is the default.

Answer: (A)

Mixing lighting is a hybrid approach: it bakes the lighting for static parts of the scene into lightmaps while dynamic objects keep real-time shadows. Real-time Global Illumination, by contrast, calculates indirect lighting on the fly, updating continuously as geometry and lights move.

This is why you’d choose mixed lighting when most of your scene is static and you want good performance. The baked light contributes to the environment without running expensive calculations every frame, and dynamic objects can still cast or receive shadows in real time. Real-time GI is the pick when lighting needs to respond to changes—moving lights, changing geometry, or interactive events—so the indirect illumination stays accurate as the scene evolves, even though it costs more at runtime.