Procedural Sky
The Procedural Sky Volume component override lets you specify the type of sky that the High Definition Render Pipeline (HDRP) generates. For example, you can set up the sun size, ground color and sky tint.
This sky is similar to the procedural sky in Unity’s built-in render pipeline. It differs as it includes extra properties that the built-in render pipeline lacks. HDRP’s Procedural Sky exposes a Multiplier, Update Mode properties, and the option to include the sun in HDRP’s baking process.
Deprecation
HDRP deprecated Procedural Sky in 2019.3 and replaced it with Physically Based Sky. To use Procedural Sky for HDRP Projects in Unity 2019.3 or later, follow the instructions on the Upgrading from 2019.2 to 2019.3 guide.
Using Procedural Sky
Procedural Sky uses the Volume framework, so to enable and modify Procedural Sky properties, you must add a Procedural Sky override to a Volume in your Scene. To add Procedural Sky to a Volume:
- In the Scene or Hierarchy view, select a GameObject that contains a Volume component to view it in the Inspector.
- In the Inspector, navigate to Add Override > Sky and click on Procedural Sky.
After you add a Procedural Sky override, you must set the Volume to use Procedural Sky. The Visual Environment override controls which type of sky the Volume uses. In the Visual Environment override, navigate to the Sky section and set the Type to Procedural Sky. HDRP now renders a Procedural Sky for any Camera this Volume affects.
API
To access and control this override at runtime, use the Volume scripting API. Because of how the Volume system works, you edit properties in a different way to standard Unity components. There are also other nuances to be aware of too, such as each property has an overrideState. This indicates to the Volume system whether to use the property value you set, or use the default value stored in the Volume Profile. For information on how to use the API correctly, see Volume scripting API.
Properties
To edit properties in any Volume component override, enable the checkbox to the left of the property. This also tells HDRP to use the property value you specify for the Volume component rather than the default value. If you disable the checkbox, HDRP ignores the property you set and uses the Volume’s default value for that property instead.
| Property | Description |
|---|---|
| Enable Sun Disk | Enable the checkbox to make HDRP display the sun disk defined by the Sky Size, Sun Size Convergence, Exposure, and Multiplier . |
| Sun Size | Use the slider to set the size modifier of the sun disk. |
| Sun Size Convergence | Use the slider to set the size convergence of the sun, smaller values make the sun appear larger. |
| Atmospheric Thickness | Use the slider to set the density of the atmosphere, an atmosphere of higher density absorbs more light. |
| Sky Tint | Use the color picker to select the color of the sky. |
| Ground Color | Use the color picker to select the color of the ground (the area below the horizon). |
| Exposure | Set the exposure for HDRP to apply to the Scene as environmental light. HDRP uses 2 to the power of your Exposure value to calculate the environment light in your Scene. |
| Multiplier | Set the multiplier for HDRP to apply to the Scene as environmental light. HDRP multiplies the environment light in your Scene by this value. |
| Update Mode | Use the drop-down to set the rate at which HDRP updates the sky environment (using Ambient and Reflection Probes). • On Changed: HDRP updates the sky environment when one of the sky properties changes. • On Demand: HDRP waits until you manually call for a sky environment update from a script. • Realtime: HDRP updates the sky environment at regular intervals defined by the Update Period. |
| - Update Period | Set the period (in seconds) for HDRP to update the sky environment. Set the value to 0 if you want HDRP to update the sky environment every frame. This property only appears when you set the Update Mode to Realtime. |