# Diffusion Profile List

The High Definition Render Pipeline (HDRP) allows you to use up to 15 custom [Diffusion Profiles](diffusion-profile-reference.md) in view at the same time. To use more than 15 custom Diffusion Profiles in a Scene, you can use the **Diffusion Profile List** inside a [Volume](understand-volumes.md). This allows you to specify which Diffusion Profiles to use in a certain area (or in the Scene if the Volume is global).

## Add a Diffusion Profile List to a volume

To add a **Diffusion Profile List** to a Volume:

1. Select the Volume component in the Scene or Hierarchy to view it in the Inspector
2. In the Inspector, go to **Add Override** and select **Diffusion Profile List**.

[!include[](snippets/volume-override-api.md)]

## Properties

![](Images\Override-DiffusionProfile1.png)

[!include[](snippets/Volume-Override-Enable-Properties.md)]

| **Property**                               | **Description**                                              |
| ------------------------------------------ | ------------------------------------------------------------ |
| **Diffusion Profile List**                 | Assign a Diffusion Profile to each field to create a list of Diffusion Profiles that Materials in this Volume can use. Click the plus icon to add another field. To remove a Diffusion Profile from the list, select it in the list and click the minus icon. |
| **Fill Profile List With Scene Materials** | Select this to remove every Diffusion Profile in the **Diffusion Profile List** and then re-populate the list with Diffusion Profiles that Materials within the bounds of this local Volume use. <br/><br/>This property is only available when you select **Local** from the **Mode** drop-down in the Volume component. Add a Collider to this GameObject to set the bounds of the Volume. |

## Details

- If a Material references a Diffusion Profile that's not in the list of available Diffusion Profiles, that Material uses the default Diffusion Profile, which has a fushia tint.

- If the Volume with the Diffusion Profile List is local, the **Fill Profiles With Scene Materials** button appears. Select to fetch the Diffusion Profiles from Materials inside the Volume's bounds and fill the **Diffusion Profile List** with them.

- If multiple Volumes overlap and affect the Camera simultaneously, HDRP interpolates between multiple values for the same Volume override property to handle overlapping values. However, interpolating a final value for the **Diffusion Profile List** isn't possible. Instead, HDRP additively selects the **Diffusion Profile List** from all Volumes, by prioritizing profiles from Volumes with the highest **Priority**. If the total count exceeds the maximum capacity of 15 Diffusion Profiles, the remaining profiles are ignored.

- There is a small performance overhead to find which Diffusion Profile a Material uses. This means that the fewer Diffusion Profiles you use, the faster this process is. You can use the **Diffusion Profile List** component in local volumes to optimize the search process. If you have multiple Scenes, and each one only uses a single Diffusion Profile, you can use this override in a separate Volume in each Scene to select a Diffusion Profile per Scene, instead of placing the Diffusion Profile from each Scene into the volume of the [HDRP Graphics settings window](Default-Settings-Window.md). This reduces the resource intensity of the search in the Shader.This is particularly effective if your Scene contains a lot of pixel overdraw to produce visual effects like foliage and vegetation.