Bake Lighting in a 3D Scene

Bake a small Scene’s sky and bounced light, then compare the result with live lighting. Baked Lighting (GI) stores lightmaps for still geometry. Moving Objects continue to use real-time light.

Prerequisites

Open a 3D Scene with visible ground, blocks, or supported still geometry. Configure the sky, sun, and lighting you want to bake. Save a checkpoint and begin with a small Scene.

Run a Draft Bake

1. Choose Object Mode and open Rendering > Baked Lighting (GI).
2. Enable Use Baked Lighting and choose the Draft quality option for the first check.
3. Retain Sky Light 1, Bounce Light 1, and Brightness 1 while comparing the initial result.
4. Choose Bake Lighting. The progress dialog reports the work and has Cancel; Escape or closing the backdrop also cancels it.
5. Wait for a completed result and inspect the status. Compare lit and shadowed faces in the editor and a fresh game run.
6. Save, reopen, and check that the baked result and settings remain present.

Expected result: the status reports a current bake and the running Scene applies the stored light to the supported still surfaces. A completed bake doesn’t replace checks of imported models, seams, material appearance, or the target device.

If Bake Lighting is disabled, read its reason. The authoring viewport must be available for the bake, and the Scene needs supported geometry. A property panel mounted without its renderer can show the fields while the bake itself is unavailable.

Compare Quality Settings

Quality offers Draft, Balanced, and High. Draft is useful while adjusting geometry and appearance; compare Balanced before committing to a final result. High can require more work and larger output. Measure the actual Scene rather than relying on the label’s timing estimate.

Setting	What it changes
Sky Light	The baked sky contribution, from 0 to 2.
Bounce Light	The baked bounce contribution, from 0 to 2.
Brightness	The applied result’s intensity, from 0 to 4.
Texels per block (0 = preset)	The lightmap density override. Higher density increases traced work and stored pixels.
Rays per texel (0 = preset)	Sampling override for each lightmap texel.
Light bounces (0 = preset)	Bounce-count override.
Max page size (0 = preset)	The atlas page-size override.
Softening	Edge-aware smoothing of the traced result.
Gutter Padding (Texels)	Padding around packed surface charts.

The advanced fields labeled 0 = preset choose the quality preset’s value when zero. In particular, a Light bounces value of 0 selects that preset; it doesn’t request a zero-bounce bake. Use Bounce Light 0 when suppressing the baked bounce contribution is the intended operation.

Check Stale Results

The panel compares the current Scene’s bake inputs with the saved result. Geometry, ground, sky, sun, or bake-setting changes can report Scene changed since the last bake. Re-bake after those changes and check the result again.

Moving Objects retain live lighting. In a Scene with a moving day/night sun, the sun’s direct light can change while the baked bounce still reflects its authored bake position. Test the times of day the game actually uses.

The panel warns when real-time GI is also enabled because the sun’s bounce can be counted twice. Compare the Scene with one intended bounce system enabled before increasing brightness to compensate for an unexpected result.

Keep or Remove the Bake

Turn Use Baked Lighting off to retain the result while lighting the Scene live. Use Clear to remove its lightmaps from the project; the settings stay. A large bake can add stored image data, so clear unwanted results before retaining many experimental copies.

In a 3D Logic workspace, Change Baked Lighting Property changes the existing result. Choose Property enabled with a Boolean Value, or brightness with a numeric Value. For brightness, Seconds 0 applies immediately; a positive duration fades to the new value. Test switching the result and a short brightness fade in a Scene that already has a bake. This Action doesn’t trace a new bake during gameplay.

Troubleshooting

Symptom	Check
Bake Lighting is unavailable	Read the disabled reason, then check the active viewport and supported still geometry.
The result looks old	Check the stale status and re-bake after changing an input.
A moving Object looks different	It uses real-time light; compare the live lighting at its position.
The Scene is unexpectedly bright	Check real-time GI, baked bounce, and applied Brightness.
Seams or noise are visible	Compare quality, samples, chart padding, and Softening on a small representative area.
Runtime controls have no visible effect	Check that the Scene has a bake and Use Baked Lighting is enabled.