[GIProbe]s are used to provide high-quality real-time indirect light to scenes. They precompute the effect of objects that emit light and the effect of static geometry to simulate the behavior of complex light in real-time. [GIProbe]s need to be baked before using, however, once baked, dynamic objects will receive light from them. Further, lights can be fully dynamic or baked.
Having [GIProbe]s in a scene can be expensive, the quality of the probe can be turned down in exchange for better performance in the [ProjectSettings] using [member ProjectSettings.rendering/quality/voxel_cone_tracing/high_quality].
[b]Procedural generation:[/b] [GIProbe] can be baked in an exported project, which makes it suitable for procedurally generated or user-built levels as long as all the geometry is generated in advance.
[b]Performance:[/b] [GIProbe] is relatively demanding on the GPU and is not suited to low-end hardware such as integrated graphics (consider [BakedLightmap] instead). To provide a fallback for low-end hardware, consider adding an option to disable [GIProbe] in your project's options menus. A [GIProbe] node can be disabled by hiding it.
[b]Note:[/b] Meshes should have sufficiently thick walls to avoid light leaks (avoid one-sided walls). For interior levels, enclose your level geometry in a sufficiently large box and bridge the loops to close the mesh. To further prevent light leaks, you can also strategically place temporary [MeshInstance] nodes with [member GeometryInstance.use_in_baked_light] enabled. These temporary nodes can then be hidden after baking the [GIProbe] node.
[b]Note:[/b] Due to a renderer limitation, emissive [ShaderMaterial]s cannot emit light when used in a [GIProbe]. Only emissive [SpatialMaterial]s can emit light in a [GIProbe].
Bakes the effect from all [GeometryInstance]s marked with [member GeometryInstance.use_in_baked_light] and [Light]s marked with either [constant Light.BAKE_INDIRECT] or [constant Light.BAKE_ALL]. If [code]create_visual_debug[/code] is [code]true[/code], after baking the light, this will generate a [MultiMesh] that has a cube representing each solid cell with each cube colored to the cell's albedo color. This can be used to visualize the [GIProbe]'s data and debug any issues that may be occurring.
[b]Note:[/b] [method bake] works from the editor and in exported projects. This makes it suitable for procedurally generated or user-built levels. Baking a [GIProbe] generally takes from 5 to 20 seconds in most scenes. Reducing [member subdiv] can speed up baking.
Offsets the lookup of the light contribution from the [GIProbe]. This can be used to avoid self-shadowing, but may introduce light leaking at higher values. This and [member normal_bias] should be played around with to minimize self-shadowing and light leaking.
[b]Note:[/b] [code]bias[/code] should usually be above 1.0 as that is the size of the voxels.
The size of the area covered by the [GIProbe]. If you make the extents larger without increasing the subdivisions with [member subdiv], the size of each cell will increase and result in lower detailed lighting.
Number of times to subdivide the grid that the [GIProbe] operates on. A higher number results in finer detail and thus higher visual quality, while lower numbers result in better performance.
