Realtime Preview of Baked GI in Editor Using Path Tracing
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Summary
When working with baked global illumination, the lighting data in the scene of the Unity Editor becomes invalidated as soon as the creator moves a light, modifies the geometry or changes a material. To see updates to baked lighting data after these modifications, the scene needs to be rebaked, the process of which can take time and deeply impacts the speed at which you are able to iterate on your content.
Use Case / Intended Outcome
For faster previews of baked lighting we provide a dedicated preview path for iterating on baked lighting data more quickly.
Using the “backwards” path tracing pipeline (where light paths are generated starting from the camera) to compute lighting only for the visible parts of a scene, we enable creators to preview the illumination "instantaneously". This feature will take advantage of hardware accelerated ray tracing if this is available, and will also work on older GPUs using a compute shader fallback.