Lighting

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Scenes are lit by the sun or moon, the sky, and the lights you place. For interiors, caves and alleys, baked light probes replace the flat outdoor ambient with bounce light and sky visibility, so enclosed spaces darken naturally and take on their lamps’ colour. Screen-space reflections and screen-space bounce lighting add dynamic detail on top.

The sun’s position, the time of day and the lighting looks are covered in Sky, weather and climate.

Add a light

Select an object, such as a lamp post or a torch model.
In the Details panel, click Add Component → Light.
Pick a Preset, then adjust the fields. Applying a preset keeps the light’s offset on the object.

Preset	Kind	Description
Candle	Point	A small warm flame that flickers
Torch	Point	Warm, flickering, casts shadows
Lantern	Point	Lights up at night
Lamp	Point	A neutral electric lamp
Neon	Point	A saturated neon glow
Spotlight	Spot	A crisp cone with shadows
God Rays	Spot	A soft volumetric spot that draws shafts through the fog
Moonlight	Directional	A cool moonlight for night scenes
Key Light	Directional	A strong warm key light, like a second sun
Rim Light	Directional	A soft cool rim light without shadows

Light settings

Setting	Field	Range	Default	Description
Kind	`kind`	Point / Spot / Directional	Point	A directional light shines straight down until you rotate the object
Colour	`color`	sRGB	White
Temperature	`temperature`	1,000–12,000 K in the panel; 0 turns it off	0	1,000 is a candle, 2,700 a lamp, 6,500 daylight
Intensity	`intensity`	Up to 200,000 lm (point, spot) or 150,000 lux (directional)	12,000
Range	`range`	0.5–100 m in the panel, up to 200 by command	14 m	Point and spot only
Cone	`spot_angle`	1–89°	35°	Spot only
Hard edge	`inner_angle`	0 (soft) – 1 (hard)	0.8	Spot only
Source radius	`source_radius`	0–2 m in the panel, up to 10 by command	0	Larger values give softer highlights
Offset	`offset`	−100 to 100 m	—	Position relative to the object, for example the lamp head
Flicker	`flicker`	0 (steady) – 1 (wild)	0
Cast shadows	`shadows`	On/off	Off
Only at night	`night_only`	On/off	On	Fades the light in only when the sun is down
Volumetric	`volumetric`	On/off	Off	Lights the volumetric fog, for halos and shafts. Needs volumetric fog turned on

Change lights from scripts

During Play, scripts dim, brighten or recolour a light object:

Function	Description
`set_light(id, brightness)`	Scales the light’s authored brightness, from 0 (off) to 20. A colour set earlier is kept
`set_light(id, brightness, r, g, b)`	The same, with a new sRGB colour (each 0–1)

The scale applies on top of Only at night and Flicker. Press Stop to restore the authored lights.

// A world script: the light object named "Alarm lamp" pulses red.
fn update(dt) {
    let lamp = find("Alarm lamp");
    set_light(lamp, 1.0 + (elapsed * 6.0).sin(), 1.0, 0.1, 0.05);
}

Bake light probes

Light probes are baked on the CPU with a path tracer; no GPU is needed. A bake traces the models, built-in props and landscape near each probe, with albedo from their materials, lit by your lights, the sun or moon at the bake hour, and the ambient sky.

There are two kinds:

Irradiance volumes are boxes of ambient samples. Inside the box, the baked bounce light and sky visibility replace the flat ambient and sky light, blending out over the last metre.
Reflection probes capture a cubemap at their centre, used for reflections and diffuse light inside their box.

Open Window → World & terrain → Light probes.
Click Add volume or Add reflection probe. The probe bounds draw in the viewport.
Set the probe’s centre, size and yaw to cover the room or cave.
Click Bake on the probe, or Bake all.

Each probe shows its status: baked, unbaked (no effect until baked), stale (the scene near it changed since the bake, including objects, lights, the sky or the bake settings), or missing (the baked file is not in the asset cache). Re-bake stale probes. Turn off Draw probes to compare against flat ambient.

Volume setting	Field	Range	Default
Size	`size`	0.5–1,000 m per axis	—
Yaw	`yaw`	−180 to 180° in the panel	0
Resolution	`resolution`	1–32 samples per axis; about one per 1.5–3 m	—
Bounce strength	`intensity`	0–4 in the panel, up to 16 by command	1
Fill	`fill`	0–1	0.7

Fill is the share of sky and ambient light kept however enclosed the space is. 0 is physically dark; graded, stylized scenes can turn low values to black.

Reflection setting	Field	Range	Default
Size, Yaw	`size`, `yaw`	As for volumes	—
Resolution	`resolution`	32, 64, 128 or 256	128
Intensity	`intensity`	0–4 in the panel, up to 16 by command	—

Bake settings

Setting	Field	Range	Default
Rays	`rays`	16–1,024 in the panel, up to 4,096 by command	128 per ambient-cube face
Bounces	`bounces`	1–4	2
Ray reach	`max_distance`	5–300 m in the panel, up to 1,000 by command	80 m
Own bake hour / Bake hour	`hour`	0–23.9 h; −1 uses the environment’s time of day	−1
Re-bake on destruction	`runtime_rebake`	On/off	On

With Re-bake on destruction on, destroying objects inside a probe during Play re-bakes it in the background without them. A 16 × 6 × 16 m room at the default settings bakes in about a second.

Sun shadows

Open Window → World & terrain → Post process and expand Sun shadows.

Setting	Field	Range	Default
Cascades	`cascades`	1–4	4
Map size	`map_size`	512, 1024, 2048, 4096 texels	2048
Sharp shadows reach (m)	`first_cascade_far_bound`	1–100 m in the panel	12 m
Shadow distance (m)	`max_distance`	0–1,000 m in the panel; 0 follows the fog distance	0
Depth bias	`depth_bias`	0–0.2 in the panel	0.02
Normal bias	`normal_bias`	0–10	1.8

More cascades give sharper near and far shadows at more cost. Raise Depth bias if surfaces show striped shadow acne, and Normal bias if slopes do; too much normal bias detaches shadows from objects. The player’s graphics quality sets the shadow map size: 1024 on Low, 2048 on Medium and 4096 on High.

Reflections and bounce lighting

Both effects are in the Post process tab. They switch the camera to the deferred renderer and replace MSAA with SMAA or TAA.

Setting	Section	Default	Description
Screen-space reflections	Reflections and film	Off	Wet stone, water and metal reflect what is on screen
Reflective below roughness	Reflections and film	0.35	Surfaces smoother than this reflect. Terrain layers set their own roughness
Bounce lighting (screen-space GI)	Global illumination	Off	One bounce of diffuse light from what is on screen: a sunlit red wall tints the floor beside it
Bounce intensity	Global illumination	1	0–4; 1 is physically based
Bounce distance (m)	Global illumination	6 m	0.5–30 m; longer reaches across rooms but costs more and misses small detail

Bounce lighting traces at half resolution and smooths over frames. It is off on the Low graphics setting.

Limits

Up to 8 irradiance volumes and 8 reflection probes are drawn per view.
A bake processes up to 32 probes per command.
Screen-space effects only see what is on screen.

Automate it

This places a torch, adds an irradiance volume around a room, and bakes it:

feather-cli --connect .feather-session.json command light.add \
  --json '{"preset":"torch","position":[2,1.5,-4],"name":"Hall torch"}'

feather-cli --connect .feather-session.json command probe.add \
  --json '{"kind":"volume","value":{"id":"hall","center":[0,3,-4],"size":[16,6,16],"resolution":[8,3,8]}}'

feather-cli --connect .feather-session.json command lighting.bake_probes \
  --json '{"ids":["hall"]}'

Command	Purpose
`light.add`	Places a preset light as a new object
`scene.update`	Adds or edits a `light` on an object
`lighting.get` / `lighting.set`	Reads probe status; patches `probes_enabled` and `bake` settings
`probe.add` / `probe.update` / `probe.remove`	Edits irradiance volumes and reflection probes
`lighting.bake_probes`	Bakes probes; `stale_only` re-bakes only unbaked, stale or missing ones
`project.environment`	Patches the sun `shadows` settings
`project.post_process`	Turns screen-space reflections and bounce lighting on or off

See Agents & automation for connecting a live session.