Lights in the High Definition Render Pipeline
Use the Light component to create light sources in your Scene. The Light component controls the shape, color, and intensity of the light. It also controls whether or not the Light casts shadows in your Scene, as well as more advanced settings.
Creating Lights
There are two ways to add Lights to your Scene. You can create a new Light GameObject, or you can add a Light component to an existing GameObject.
To create a new Light Gameobject:
- In the Unity Editor, go to GameObject > Light
- Select the Light type you want to add.
Unity creates a new GameObject and attaches a Light component, as well as two other High Definition Render Pipeline (HDRP) components: HD Additional Light Data and HD Additional Shadow Data. Unity places the new Light GameObject into your Scene, centered on your current view in the Scene window.
To add a Light component to an existing GameObject:
- Select the GameObject you want to add a Light.
- In the Inspector, click Add Component.
- Go to the Rendering section, and click Light. This creates a new Light source and attaches it to the currently selected GameObject. It also adds the HD Additional Light Data and HD Additional Shadow Data HDRP components.
Alternatively, you can search for "Light" in the Add Component window, then click Light to add the Light component.
Configuring Lights
To configure the properties of a Light, select a GameObject in your Scene with a Light component attached. See the Light’s properties in the Inspector window.
HDRP includes multiple types of Light. Although HDRP Lights share many properties, each one has its own unique behavior and set of properties.
For more detailed information on how to configure realistic light fixtures, see the Create High-Quality Light Fixtures in Unity expert guide.
Properties
The properties available for Lights are in separate drop-down sections. Each drop-down section contains some properties that all Lights share, and also properties that customize the behavior of the specific type of Light. These sections also contain advanced properties that you can expose if you want to fine-tune your light's behavior. The drop-down sections are:
General
General properties control the type of Light, how HDRP processes this Light, and whether this Light affects everything in the Scene or just GameObjects on a specific Light Layer.
| Property | Description |
|---|---|
| Type | Defines the Light’s type. Lights of different Types behave differently, so when you change the Type, the properties change in the Inspector. |
| Mode | Specify the Light Mode that HDRP uses to determine how to bake a Light, if at all. Possible modes are: • Realtime • Mixed • Baked |
| Light Layer | A mask that allows you to choose which Light Layers this Light affects. The affected Light only lights up Mesh Renderers with a matching Rendering Layer Mask. To expose this property, enable the advanced properies for this section. |
Light Types guide
| Type | Description |
|---|---|
| Spot | Emits light from a specified location and range over which the light diminishes. A Spot Light constrains the light it emits to an angle, which results in a cone-shaped region of illumination. The center of the cone points in the forward direction (z-axis) of the Light GameObject. Light also diminishes at the edges of the Spot Light’s cone. Increase the Spot Angle to increase the width of the cone. |
| Directional | Creates effects that are similar to sunlight in your Scene. Like sunlight, Directional Lights are distant light sources that HDRP treats as though they are infinitely far away. A Directional Light does not have any identifiable source position, and you can place the Light GameObject anywhere in the Scene. A Directional Light illuminates all GameObjects in the Scene as if the Light rays are parallel and always from the same direction. The Light disregards the distance between the Light itself and the target GameObject, so the Light does not diminish with distance. |
| Point | Projects light out equally in all directions from a point in space. The direction of light hitting a surface is the line from the point of contact back to the center of the Light GameObject. The light intensity diminishes with increased distance from the Light, and it reaches zero at the distance specified in the Range field. Light intensity is inversely proportional to the square of the distance from the source. This is known as the Inverse-square law, and is similar to how light behaves in the real world. |
| Rectangle | Projects light from a rectangle. Light shines in all directions uniformly from the surface of the rectangle. |
| Tube | Emits light in all directions equally along a line in space. |
Shape
These settings define the area this Light affects. Each Light Type has its own unique Shape properties.
Spot Light
| Property | Description |
|---|---|
| Shape | HDRP Spot Lights can use three shapes.Cone : Projects light from a single point at the GameObject’s position, out to a circular base, like a cone. Alter the radius of the circular base by changing the Spot Angle and the Range.Pyramid : Projects light from a single point at the GameObject’s position onto a base that is a square with its side length equal to the diameter of the Cone.Box : Projects light evenly across a rectangular area defined by a horizontal and vertical size. |
| Outer Angle | The angle in degrees at the base of a Spot Light’s cone. This property is only for Lights with a Cone Shape. |
| Inner Angle (%) | Determines where the attenuation between the inner cone and the outer cone starts. Higher values cause the light at the edges of the Spot Light to fade out. Lower values stop the light from fading at the edges. This property is only for Lights with a Cone Shape. |
| Spot Angle | The angle in degrees at the base of a Spot Light’s cone. |
| Aspect Ratio | Adjusts the shape of a Pyramid Spot Light to create rectangular Spot Lights. Set this to 1 for a square projection. Values lower than 1 make the Light wider, from the point of origin. Values higher than 1 make the Light longer. This property is only for Lights with a Pyramid Shape. |
| Emission Radius | The radius of the light source. |
| Max Smoothness | For Cone and Pyramid. Changes the specular highlight in order to mimic a spherical Light. This allows you to avoid very sharp specular highlights that do not match the shape of the source Light. |
| Size X | For Box. Adjusts the horizontal size of the Box Light. No light shines outside of the dimensions you set. |
| Size Y | For Box. Adjusts the vertical size of the Box Light. No light shines outside of the dimensions you set. |
Directional Light
| Property | Description |
|---|---|
| Sun Highlight Disk Size | Defines the size of the sun disk’s highlight. The angle of the sun cone in degrees. |
| Sun Highlight Halo Size | Defines the size of the halo which surrounds the sun disk. |
| Max Smoothness | Allows you to alter the specular highlight. This allows you to avoid very sharp specular highlights that do not match the shape of the Light source. |
Point Light
| Property | Description |
|---|---|
| Emission Radius | Defines the radius of the light source. |
| Max Smoothness | Allows you to alter the specular highlight. This allows you to avoid very sharp specular highlights that do not match the shape of the Light source. Acts as a less resource-intensive method for faking spherical lighting. |
Rectangle Light
| Property | Description |
|---|---|
| Size X | Defines the horizontal size of the Rectangle Light. |
| Size Y | Defines the vertical size of the Rectangle Light. |
Tube Light
| Property | Description |
|---|---|
| Length | Defines the length of the Tube Light. The center of the Light is the Transform Position and the Light itself extends out from the center symmetrically. The Length is the distance from one end of the tube to the other. |
Emission
These settings define the emissive behavior of your Light. You can set the Light’s color, strength, and maximum range. If you do not see these properties in the Light Inspector, make sure you expose the advanced properties. Most Lights share Emission properties. Below are the list of properties that more than one Light Type share, followed by unique properties only available for a single Light Type.
Shared Properties
| Property | Description |
|---|---|
| Color Temperature | Enable the checkbox to set the color temperature mode for this Light. Color Temperature mode adjusts the color of your Light based on a red-to-blue kelvin temperature scale. When enabled, this hides the Color property and exposes Filter and Temperature. Disable this checkbox to only display the Color field in the Inspector and use that as the Light color, without the temperature. |
| - Filter | Allows you to select the color of the Light’s filter using the colour picker. HDRP uses this and the Temperature property to calculate the final color of the Light. |
| - Temperature | Allows you to select a temperature that HDRP uses to calculate a color on a red-to-blue kelvin temperature scale. You can move the slider along the scale itself, or specify an exact temperature value in the field to the right of the slider scale. |
| Color | Allows you to select the color of the Light using the colour picker. |
| Intensity | The strength of the Light. Intensity is expressed in the following units: • A Spot Light can use Lumen, Candela, Lux, and EV100. • A Directional Light can only use Lumen, Candela, Lux, and EV100. • A Point Light can use Lumen and Candela. • A Rectangle Light can use Lumen, Luminance, and EV100. • A Tube Light can use Lumen, Luminance, and EV100. Generally, the further the light travels from its source, the weaker it gets. The only exception to this is the Directional Light which has the same intensity regardless of distance. For the rest of the Light types, lower values cause light to diminish closer to the source. Higher values cause light to diminish further away from the source. |
| Range | The range of influence for this Light. Defines how far the emitted light reaches. This property is available for all Light Types except Directional. |
| Indirect Multiplier | The intensity of indirect light in your Scene. A value of 1 mimics realistic light behavior. A value of 0 disables indirect lighting for this Light. If both Realtime and Baked Global Illumination are disabled in Lighting Settings (menu: Window > Rendering > Lighting Settings), the Indirect Multiplier has no effect. |
| Cookie | An RGB Texture that the Light projects. For example, to create silhouettes or patterned illumination for the Light. Texture shapes should be 2D for Spot and Directional Lights and Cube for Point Lights. Always import Cookie textures as the default texture type. This property is available for Spot, Directional, and Point Lights. |
| Affect Diffuse | Enable the checkbox to apply diffuse lighting to this Light. To expose this property, enable the advanced properies for this section. |
| Affect Specular | Enable the checkbox to apply specular lighting to this Light. To expose this property, enable the advanced properies for this section. |
| Range Attenuation | Enable the checkbox to make this Light shine uniformly across its range. This stops light from fading around the edges. This setting is useful when the range limit is not visible on screen, and you do not want the edges of your light to fade out. This property is available for all Light Types except Directional. To expose this property, enable the advanced properies for this section. |
| Fade Distance | The distance between the Light source and the Camera at which the Light begins to fade out. Measured in meters. This property is available for all Light Types except Directional. To expose this property, enable the advanced properies for this section. |
| Dimmer | Dims the Light. Does not affect the intensity of the light. You can also modify this property via Timeline, Scripting or animation. The parameter lets you fade the Light in and out without having to store its original intensity. To expose this property, enable the advanced properies for this section. |
| Display Emissive Mesh | Enable the checkbox to make Unity automatically generate a Mesh with an emissive Material using the size, colour, and intensity of this Light. Unity automatically adds the Mesh and Material to the GameObject the Light component is attached to. This property is available for Rectangle and Tube Lights. To expose this property, enable the advanced properies for this section. |
Spot Light
| Property | Description |
|---|---|
| Reflector | Enable the checkbox to simulate a reflective surface behind the Spot Light. Spot Lights are Point Lights that are partly occluded at the back by a reflective surface. Simulating this reflective surface increases the intensity of the Spot Light because the reflective surface reflects light originally directed backwards to focus the intensity in the Spot Light’s direction. |
Directional Light
| Property | Description |
|---|---|
| Size X | The horizontal size of the projected cookie texture in pixels. Set a Cookie in the Light Inspector to expose this property. |
| Size Y | The vertical size of the projected cookie texture in pixels. Set a Cookie in the Light Inspector to expose this property. |
Volumetrics
These settings define the volumetric behavior of this Light. Alter these settings to change how this Light behaves with Atmospheric Scattering. All Light Types share the same Volumetric properties.
Shared Properties
| Property | Description |
|---|---|
| Enable | Enable the checkbox to simulate light scattering through volumetric fog. Enabling this property allows you to edit the Dimmer and Shadow Dimmer properties. |
| Dimmer | Dims the volumetric lighting effect of this Light. |
| Shadow Dimmer | Dims the volumetric fog effect of this Light. Set this property to 0 to make the volumetric scattering compute faster. |
Shadows
Use the Shadows section to adjust the Shadows cast by this Light. HDRP currently does not support shadowing Tube Lights. Because of this, Unity does not expose the Shadows drop-down section in the Inspector when you select either of this Type. The Light Types that HDRP does support shadowing for (Spot, Directional, and Point) share almost all of their properties.
Unity exposes extra properties in the Shadows section depending on the Mode you set in the General section. It also exposes extra properties depending on the Filtering Quality set in your Unity Project’s HDRP Asset. To change the Filtering Quality property, navigate to your Project’s HDRP Asset > Shadows and use the Filtering Quality drop-down to select the shadow filtering mode. Setting Filtering Quality to High or Very High exposes extra properties in the Light Inspector’s Shadow drop-down section.
• For more information on shadow filtering in HDRP, see the documentation on Shadow Filtering.
• For a list of the the available filter quality presets in HDRP, see the Filtering Qualities table.
Properties
Shadow Map
| Property | Description |
|---|---|
| Enable | Enable the checkbox to add shadows to this Light. |
| Resolution | The resolution of this Light’s shadow maps. Measured in pixels. A higher resolution increases the fidelity of shadows at the cost of GPU performance and memory usage, so if you experience any performance issues, try using a lower value. |
| Near Plane | The distance, in meters, from the Light that GameObjects begin to cast shadows. |
| Shadowmask Mode | Defines how the shadowmask behaves for this Light. For detailed information on each Shadowmask Mode, see the documentation on Shadowmasks. This property is only visible if you tet the Mode, under General, to Mixed. |
| View Bias Scale | Defines how much the View Bias scales with distance for this Light. Surfaces directly illuminated by a Light can sometimes appear to be partly in shadow and parts of the surface might be incorrectly illuminated due to low-resolution shadow maps or shadow filtering. If the shadows that this Light casts appear incorrectly, use the slider to adjust this value until they are correct. |
| View Bias | The minimum View Bias for this Light. For more information about View Bias in HDRP, see documentation on Shadows. To expose this property, enable the advanced properies for this section. |
| Normal Bias | Controls the amount of normal bias this Light applies along the normal of the illuminated surface. To expose this property, enable the advanced properies for this section. |
| Edge Leak Fixup | Enable the checkbox to prevent light leaking at the edge of shadows this Light casts. To expose this property, enable the advanced properies for this section. |
| - Edge Tolerance Normal | Enable the checkbox to use the edge leak fix in normal mode. Uncheck this box to use the edge leak fix in view mode. To expose this property, enable the advanced properies for this section. |
| - Edge Tolerance | The threshold, between 0 and 1, which determines whether to apply the edge leak fix. To expose this property, enable the advanced properies for this section. |
| Dimmer | Dims the shadows this Light casts so they become more faded and transparent. To expose this property, enable the advanced properies for this section. |
| Fade Distance | The distance, in meters, between the Camera and the Light at which shadows fade out. This property is available for Spot and Point Lights. To expose this property, enable the advanced properies for this section. |
High Filtering Quality properties
In your HDRP Asset, select High from the Filtering Quality drop-down to expose the following properties.
| Property | Description |
|---|---|
| Shadow Softness | Defines the behavior of area light shadows. Higher softness values mimic a larger emission radius while lower values punctual light shadows. High values increase shadow blur depending on the distance between the pixel receiving the shadow and the shadow caster. |
| Blocker Sample Count | The number of samples HDRP uses to evaluate the distance between the pixel receiving the shadow and the shadow caster. Higher values give better accuracy. |
| Filter Sample Count | The number of samples HDRP uses to blur shadows. Higher values give smoother results. |
| Minimal size of the filter | The minimum size of the whole shadow’s blur effect, no matter the distance between the pixel and the shadow caster. Higher values give blurrier results. |
Very High Filtering Quality properties
In your HDRP Asset, select Very High from the Filtering Quality drop-down to expose the following properties. These properties only apply to Directional Lights. Spot and Point Lights use High when you select the Very High option from the Filtering Quality drop-down.
| Property | Description |
|---|---|
| Kernel size | The size of the kernel that HDRP uses to process filtering. Larger values make shadows appear softer. |
| Light Angle | Represents the radius of the sun in the sky. It controls the acceleration of the shadow softness. |
| Max Depth Bias | The depth bias value for the maximum region size that the kernel can use. |
Contact Shadows
| Property | Description |
|---|---|
| Enable | Enable the checkbox to add Contact Shadows to this Light. |
Baked Shadows
Set the Mode, under General, to Mixed or Baked to expose the following properties.
| Property | Description |
|---|---|
| Radius | The emission radius of the light for calculating baked shadows (shadowmask or fully baked light). Higher values simulate a bigger light source and result in softer shadows. Small values simulate a small light source and result in sharper shadows. |