Baker
BakerThe Baker tab controls what is built and the quality of the saved lighting. These settings affect the next bake. Changing them does not improve data that has already been baked.
For a step-by-step setup, use First bake. For scene objects, use Placeables.
Baker settings are saved per level. You can copy them with Import settings from other level, or save starting defaults for unconfigured levels in this project. Neither action transfers an existing bake.
Bake Lighting
Builds lighting for the visible level setup, including eligible surface lightmaps, enabled probe fields, and enabled Spectral baked static shadows. Load and show the levels that should participate before starting.
Before rendering, Spectral checks the baking configuration. On Windows this includes DX12, SM6, hardware ray tracing, path tracing, and static lighting support. A competing GPU Lightmass backend, unavailable ray tracing, or an invalid stationary-light channel setup can prevent the bake from starting. Fix the reported prerequisite rather than increasing quality settings.
A successful bake is not a save operation. Save the affected levels and lighting build data afterward.
Vulkan is blocked for lighting bake creation. For a Vulkan runtime target, restart the Windows editor with -dx12, bake using the required authoring configuration, save the result, then restart on Vulkan for playback.
Cancel Bake
Replaces the bake action while a bake is active. Stops the current operation. Cancellation is not a completed build, so do not judge final quality or assume all requested lighting data was produced.
Bake preparation can update level state, including enabling precomputed lighting on participating levels and repairing light identifiers. Review and save affected levels. Spectral does not turn disabled lights on for you.
Bake Reflections
Bake ReflectionsUpdates reflection captures in visible levels. It is separate from Bake Lighting: capture reflections after the scene's lighting is ready so the cubemaps contain the intended result.
Use this after moving a box capture, changing captured geometry or lighting, or changing its source cubemap. The action changes to Cancel Reflections during an active reflection update.
General
Bake Mode
Default: Full. Choices: Full, Fast.
Controls lightmap resolution for this bake, not ray sampling. Full uses the authored Resolution Scale. Fast uses 30% of that scale, with a minimum supported scale applied.
Lowering the linear resolution reduces the number of texels substantially. This makes Fast useful for checking broad lighting, but small shadows and UV detail can disappear. A clean-looking Fast bake is not proof that the final-resolution bake has enough samples.
This setting does not reduce probe density. Probe density comes from each volume's Voxel Size.
Ray Mode
Default: Full. Choices: Full, Fast.
Controls sampling and bounce work independently of Bake Mode. Full uses the configured quality. Fast reduces ray work for lightmaps and probes while retaining the chosen resolution and denoiser.
Use Full resolution with Fast rays to inspect coverage, or Fast resolution with Full rays to compare broad lighting with less sampling noise. For a final quality comparison, check both mode selectors; changing only one does not restore the other.
Settings reference
| Group | Controls |
|---|---|
| Quality and denoising | GI and stationary shadow samples, denoisers, probe contrast, irradiance caching, ray guiding, workload |
| Lightmap storage | Resolution Scale, atlas size, compression, UV upgrade suggestions, seam stitching |
Listed defaults are Spectral's factory values. Saved project level defaults or imported settings can replace those starting values. Existing configured maps keep their own saved values. A slider can cover a smaller range than the numeric field accepts.