Version: 2019.3
Lighting Data Asset
Scene View Draw Modes for lighting

GI cache

The GI cache is an internal data cache that the Unity Editor uses to store intermediate files when precomputing lighting data for Realtime Global IlluminationA group of techniques that model both direct and indirect lighting to provide realistic lighting results. Unity has two global illumination systems that combine direct and indirect lighting.: Baked Global Illumination, and Realtime Global Illumination (deprecated).
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(deprecated), lightmapsA pre-rendered texture that contains the effects of light sources on static objects in the scene. Lightmaps are overlaid on top of scene geometry to create the effect of lighting. More info
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, Light ProbesLight probes store information about how light passes through space in your scene. A collection of light probes arranged within a given space can improve lighting on moving objects and static LOD scenery within that space. More info
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, and Reflection ProbesA rendering component that captures a spherical view of its surroundings in all directions, rather like a camera. The captured image is then stored as a Cubemap that can be used by objects with reflective materials. More info
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. By storing this data in a cache, Unity can speed up subsequent precomputations.

The cache is shared between all Unity projects on the computer, so projects with the same content and lightmapping backend can share the files.

You can manage the size, location, and compressionA method of storing data that reduces the amount of storage space it requires. See Texture Compression, Animation Compression, Audio Compression, Build Compression.
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of the cache using the GI Cache preferences. For more information, see the Preferences documentation.

Using the GI Cache

The Unity Editor uses the GI Cache when it automatically precomputes lighting data. To enable the GI Cache, open the Lighting window (menu: Window > Lighting Settings) and enable the Auto option next to the build button. This makes light data precomputations automatic, and stores data in the GI Cache.

In the Lighting window, you can clear the baked data in a SceneA Scene contains the environments and menus of your game. Think of each unique Scene file as a unique level. In each Scene, you place your environments, obstacles, and decorations, essentially designing and building your game in pieces. More info
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(disable the Auto option and choose Clear Baked Data from the BuildThe process of compiling your Project into a format that is ready to run on a specific platform or platforms. More info
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button drop-down menu). This does not clear the GI Cache, because this would increase bake time afterwards.

You can share the GiCache folder among different machines. This can make your lighting build faster, because the files are downloaded from the GiCache folder instead of computed locally. Note that the build process isn’t optimized for slow network-attached storage (NAS), so test if your bake times are severely affected before moving the cache to NAS.

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Lighting Data Asset
Scene View Draw Modes for lighting