Set composition layer transparency

Composition layers are blended according to their alpha channel. A completely opaque area of a channel obscures any layers already drawn. When you render objects to a Projection layer -- including the default scene layer -- you must make sure that the camera renders with a transparent background if you want layers behind it to be visible.

To set the main scene camera in an XR scene to render with a transparent background:

1. Select the Camera GameObject in the scene Hierarchy to view its properties in the Inspector.
2. Select from the following options. The options differ based on the render pipeline you're using:
   • Universal Render Pipeline (URP): In the Environment section, set the Background Type to Solid Color.
   • Built-In Render Pipeline: Set Clear Flags to Solid Color.
3. Select the Background color to open the color picker.
4. Set the color's A value to 0.

Tip

The main camera in an XR scene is typically a child of the Camera Offset GameObject, underneath the XR Origin. This camera is the one used to render the default scene layer, which always has a compositing order of zero. Any layers with a negative number as its compositing order are obscured by the default scene layer unless you change the camera properties to as described here.