Realtime Lighting

By default, lights in Unity - directional, spot and point, are realtime. This means that they contribute direct light to the scene and update every frame. As lights and GameObjects are moved within the scene, lighting will be updated immediately. This can be observed in both the scene and game views.

The effect of realtime light alone. Note that shadows are completely black as there is no bounced light. Only surfaces falling within the cone of the Spotlight are affected.

Realtime lighting is the most basic way of lighting objects within the scene and is useful for illuminating characters or other movable geometry.

Unfortunately, the light rays from Unity’s realtime lights do not bounce when they are used by themselves. In order to create more realistic scenes using techniques such as global illumination we need to enable Unity’s precomputed lighting solutions.