Lights and Materials¶
A scene is lit by its lights, by the sky, and in Path Traced mode by emissive surfaces. This page covers each light type and what its settings do, how the two render modes treat them differently, how to edit materials in the Material Editor, and the material settings that change how a surface takes light: emission and glass.
The two render modes share the same lights and materials, so a scene does not need to be set up twice. Path Traced mode calculates shadows, reflections and bounced light from the scene geometry. Rasterized mode is faster and approximates some of these effects; a few light settings only apply to it. See Rendering for how to switch modes.
In short
Add lights from the Scene Hierarchy's Create menu. Directional, Point and Spot lights work in both modes, but in Path Traced mode their shadows are always sharp: use an Area Light for soft path-traced shadows. Double-click a material in the Content Browser to edit it in the Material Editor. In Path Traced mode emissive materials light the scene too. Glass is a material with Transparent turned on, tuned with IOR, Attenuation, Dispersion and Tint.
Adding lights¶
Right-click an empty area of the Scene Hierarchy and choose Create, then one of:
- Directional Light
- Point Light
- Spot Light
- Area Light → Rectangle Light, Disk Light, Sphere Light or Tube Light
- Sky Light
Directional, Point, Spot and Sky lights can also be added to an existing entity with Add Component. Area lights are created only from the Create menu.
The viewport's Create (+) menu has a Spot Light button that places a Spot Light a short way in front of the surface at the centre of the view, shining along the view direction, with Cast Shadows on. With a light selected, the viewport's selection bar has an Intensity control for quick adjustment. See The viewport.
A procedural graph can also generate lights. They appear as child entities of the Procedural Mesh, each with an ordinary light component and a Generated Light component; see Generated lights.
Selected lights show their reach in the viewport: three circles at a Point Light's Radius, a cone for a Spot Light, and the outline of an Area Light's shape.
How the render modes treat lights¶
| Rasterized | Path Traced | |
|---|---|---|
| Directional, Point and Spot lights | Yes | Yes |
| Cast Shadows | Respected | Respected |
| Point and Spot Soft Shadows, Point Light Size | Soften shadows | No effect: shadows are always sharp |
| Directional Soft Shadows and Source Size | No effect: use the Scene Renderer Shadows page | No effect: shadows are always sharp |
| Area lights | Light the scene, but cast no shadows | Light the scene, with soft shadows |
| Emissive materials | The surface glows, but lights nothing else | The surface is a light source |
| Sky Light | Lights the scene | Lights the scene |
| Occlusion and reflections | Approximated by the Ambient Occlusion and Reflections settings in the Scene Renderer | Calculated from the scene geometry |
Only one Directional Light is used, in both modes. Keep a single Directional Light in each scene.
Rasterized light limit
Rasterized mode supports up to 1024 Point Lights and 1024 Spot Lights. With more, the viewport keeps working but leaves the extra lights out, and rasterized recorded frames are rejected rather than written without some of the scene's lights. Path Traced mode has no such limit.
Global shadow quality for Rasterized mode, such as shadow distance, softness and bias, is set on the Scene Renderer's Shadows page; see Scene Renderer panel.
Directional Light¶
A Directional Light is a distant light such as the sun. Its rotation sets the direction of the light; its position does not matter.
| Field | Default | What it does |
|---|---|---|
| Radiance | white | Light colour |
| Intensity | 1 |
Brightness multiplier |
| Cast Shadows | on | Whether the light casts shadows |
| Soft Shadows | on | Currently has no effect |
| Source Size | 0.5 |
Currently has no effect |
In Rasterized mode, soften directional shadows on the Scene Renderer's Shadows page instead, with Soft directional shadows, Shadow softness and, under Advanced Shadows, Directional source size scale. In Path Traced mode directional shadows are always sharp.
Point Light¶
A Point Light shines in every direction from its position.
| Field | Default | What it does |
|---|---|---|
| Radiance | white | Light colour |
| Intensity | 1 |
Brightness multiplier |
| Radius | 10 |
Reach of the light, in metres. The light fades to nothing at this distance |
| Light Size | 0.05 |
Rasterized only. Size of the light for soft shadows |
| Cast Shadows | off | Whether the light casts shadows. When off, its light passes through objects |
| Soft Shadows | off | Rasterized only. Softens the shadow edges |
Spot Light¶
A Spot Light shines a cone of light from its position, in the direction it is rotated to.
| Field | Default | What it does |
|---|---|---|
| Radiance | white | Light colour |
| Intensity | 1 |
Brightness multiplier |
| Angle | 60 |
Full width of the cone, in degrees, from 1 to 160 |
| Angle Attenuation | 5 |
How the light fades towards the edge of the cone. Higher values keep it bright closer to the edge, for a harder edge |
| Range | 10 |
Reach of the light, in metres. The light fades to nothing at this distance |
| Cast Shadows | off | Whether the light casts shadows. When off, its light passes through objects |
| Soft Shadows | off | Rasterized only. Softens the shadow edges |
In Rasterized mode the softness of spot light shadows is set with Spotlight source size (m) under Advanced Shadows on the Scene Renderer's Shadows page.
Light falloff¶
Point and Spot lights use physically based falloff in both render modes: brightness drops with the square of the distance, as real light does, and fades smoothly to zero at the light's Radius or Range. Set Radius or Range to roughly the distance the light needs to reach.
Upgrading from 2026.2
The Falloff field has been removed from the Point Light and Spot Light Inspectors,
because falloff is now physically based. Lights in scenes from 2026.2 can look
brighter or dimmer than before; adjust Intensity, Radius or Range to
compensate. The C# Falloff properties on
PointLightComponent and
SpotLightComponent still exist, but no
longer have any effect.
Area Light¶
An Area Light emits from a surface rather than a point, which gives the soft shadows and broad highlights of a window, a light panel or a fluorescent tube.
| Field | Default | What it does |
|---|---|---|
| Radiance | white | Light colour, multiplied by Intensity. Darker colours reduce the light output |
| Intensity | 5 |
Surface brightness, following a nits (cd/m²) convention for a white Radiance. It is not the total light output. 0 switches the light off |
| Shape | Rectangle | Rectangle, Disk, Sphere or Tube |
| Width, Height | 1, 1 |
Rectangle only. Full size in metres along the local X and Y axes |
| Radius | 0.5 |
Disk and Sphere: radius in metres. Tube: radius of the tube |
| Length | 1 |
Tube only. Full length in metres along the local X axis |
| Two Sided | off | Rectangle and Disk only. When off, only the face towards local +Z emits. When on, both faces emit, doubling the light output |
Each shape emits in its own way:
| Shape | Emits from |
|---|---|
| Rectangle | A rectangle in the local XY plane, facing +Z |
| Disk | A disk in the local XY plane, facing +Z |
| Sphere | The whole sphere, in every direction |
| Tube | The curved side of a tube along local X. The end caps do not emit |
Things to know about Area Lights:
- Size changes the light. A larger emitter gives out more light at the same Intensity, and softer path-traced shadows. Size the light with its own fields, which have a minimum of 0.01 m: the Transform's Scale does not resize it. Rotate the entity to aim a Rectangle or Disk.
- Intensity starts low. The default of
5is dim. As the Inspector tooltip suggests, try 100 to 200 for a bright panel or window, then double or halve it to suit the camera's exposure. - Shadows need Path Traced mode. In Rasterized mode an Area Light lights the scene but casts no shadows.
- The light itself is invisible. Cameras do not see the emitting surface. Add geometry for a visible light fixture.
A visible light panel in Path Traced mode
In Path Traced mode an emissive mesh is both visible and a light source, so a glowing panel can be a plane with an emissive material instead of an Area Light. See Emissive materials. In Rasterized mode, an emissive surface glows but does not light the scene.
Sky Light and the environment¶
A Sky Light lights the scene from all around and provides the background. Without one, the scene has no environment light and the background is black.
| Field | Default | What it does |
|---|---|---|
| Environment Map | none | An Environment asset to use as the sky. Choosing one turns Dynamic Sky off |
| Intensity | 1 |
Brightness of the environment, from 0 to 5 |
| Rotation | 0 |
Turns the environment around the vertical axis, in degrees |
| Lod | 0 |
Blurs the visible background |
| Dynamic Sky | on | Generates a sky from the settings below. Turning it on clears Environment Map |
| Turbidity | 2 |
Haziness of the generated sky. The minimum is 1.8 |
| Azimuth | 0 |
Compass direction of the sun in the generated sky, in radians |
| Inclination | 0 |
Angle of the sun from straight overhead, in radians. 0 puts the sun at the zenith |
The generated sky does not move the Directional Light. Rotate the Directional Light to match the sun's position.
In Path Traced mode, Lod blurs only the background the camera sees directly; the light the environment casts on the scene stays sharp. The Scene Renderer's Environment multiplier also scales the environment's brightness in path-traced Scene tabs. It is a project setting, not part of the scene, and does not change recordings; see Path Tracing.
The resolution of environment maps is a project setting: Settings → Project → Renderer → Environment Map Size (default 1024). See Settings.
The Material Editor¶
Double-click a material in the Content Browser to open it in the Material Editor, or open the editor from View → Material Editor. Right-clicking an object in the viewport and choosing Material opens the object's first material. The editor opens as a tab in the Main zone and saves the material as you edit it. To make a new material, see Creating assets.
- The strip along the top shows the project's materials, with a Search materials... box and a refresh button. Click a material to edit it.
- The left column shows a preview of the material. The Preview Settings below it change only the preview, not the material: Exposure, Bloom, a Sky Light with its Intensity, and a Directional Light with its Intensity and Direction.
- The middle column holds the material's settings.
- The right column lists the project's textures, with a Search textures... box.
Drag the dividers between the strip and the columns to resize them.
Transparent, at the top of the settings, switches the material between opaque and glass. An opaque material has these sections:
| Section | Settings |
|---|---|
| Albedo | Color, and Emission for a glowing surface |
| Normals | Use Normal Map |
| Metalness | Metalness, from 0 to 1 |
| Roughness | Roughness, from 0 (smooth) to 1 (rough) |
| UV | UV Scale tiles the textures across the surface and UV Offset shifts them |
Below them, Casts shadows sets whether the material casts shadows in Rasterized mode, and the collapsed LiDAR (NIR) section holds the settings that lidar and depth sensors read; see Authoring a material.
Albedo, Normals, Metalness and Roughness each have a texture slot to the left of their settings. To use a texture, drag it onto a slot from the Textures column or from the Content Browser; the X in the corner of a filled slot clears it. Dropping a texture onto the Normals slot turns on Use Normal Map, which is greyed out while that slot is empty.
Opening a material from the viewport
If the object has no material of its own, choosing Material in the viewport creates
one in Assets/Materials and gives it to the object. If the object uses its mesh's
material, it gets its own copy instead, so that edits do not change other objects that
use the mesh. The copy takes only the Color, Emission, Metalness,
Roughness and Casts shadows values, not textures or other settings.
Emissive materials¶
A material glows when its Emission is above zero. Set it in the Albedo section of the Material Editor. Emission ranges from 0 to 20; the glow takes its colour from the Albedo Color.
- In Path Traced mode an emissive surface is a real light source: it lights the objects around it and casts soft shadows. A ceiling panel, a screen or an indicator lamp lights its surroundings without any extra light.
- In Rasterized mode an emissive surface glows, but does not light other objects. Add a light next to it if the scene must look the same in both modes.
Keep emissive meshes simple
A part of a mesh with more than 4,096 triangles still glows in Path Traced mode, but is not treated as a light source: the light it casts on its surroundings is much noisier, and the Log shows a warning. Use simple geometry, such as a plane or a low-polygon shape, for emissive light sources. The Statistics page of the Scene Renderer shows how many lights, including emissive triangles, the path tracer is using.
Glass¶
To make a material into glass, open it in the Material Editor and turn on Transparent at the top. Glass is always fully see-through: there is no partial transparency. For darker or coloured glass, use Tint and Attenuation.
With Transparent on, the Material Editor shows the Albedo, Glass, Roughness, Normals, UV and LiDAR (NIR) sections. The Glass section has:
| Field | Range | Default | What it does |
|---|---|---|---|
| IOR | 1.0 to 2.5 | 1.5 |
Index of refraction: how strongly the glass bends and reflects light. Window glass is about 1.5, water about 1.33 |
| Attenuation | 0 to 5 | 0.5 |
How strongly light is absorbed, towards the Tint colour, as it travels through the glass. At 0 the glass behaves as a thin sheet; see below |
| Dispersion | 0 to 0.1 | 0 |
Splits light into its colours, giving rainbow fringes. Real glass is well under 0.03 |
| Tint | white | The colour that thick glass takes on. White glass stays clear, whatever the Attenuation |
The other sections refine the surface:
- Roughness frosts both the reflections and the view through the glass. Keep it low
for clear glass;
0is perfectly smooth. - Normals takes a normal map for textured, bumpy or rippled glass.
Glass thickness is not a setting: it is measured from the mesh, so the thicker parts of an
object absorb more light and look deeper in colour. Model glass as a closed mesh with a
front and a back face. For a thin pane modelled as a single plane, set Attenuation to
0: the glass then behaves as a thin sheet, which reflects light but passes it straight
through without bending or tinting it.
Path Traced mode traces light through the glass, so refraction and reflections are physically based. Rasterized mode approximates glass: it bends the image of what is already visible behind it, and reflects the environment. In Path Traced mode, choosing View → Material → Transmission in the toolbar's Path Tracing menu highlights which surfaces are glass.
Glass settings do not affect sensors
Lidar and depth sensor models ignore the Glass section. They read the material's separate LiDAR (NIR) settings. See Authoring a material and Materials and the depth model.
Upgrading from 2026.2
The Transparency, Transmission and Thickness controls have been removed.
Glass is now always fully transmissive, and its thickness is measured from the mesh.
Glass materials from 2026.2 keep their IOR and Tint, and open with
Attenuation 0.5 and Dispersion 0. Their old Transmission value is
carried over to NIR transmission in the LiDAR (NIR) section, so glass that
lidar passed through before still lets it through.
Where to go next¶
- Cameras and Exposure sets how bright the lit scene appears.
- Path Tracing covers denoisers, sampling and the view modes.
- Scene Renderer panel has the shadow, ambient occlusion and reflection settings for Rasterized mode.
- Lidar covers the near-infrared material settings that sensors read.
- Assets covers creating materials, importing textures and assigning a material by dragging it onto an object.