Ray-traced ambient occlusion

Ray-traced ambient occlusion (RTAO) is an alternative to screen space ambient occlusion that's more accurate because it uses off-screen data.

A single-channel occlusion texture of a gothic corridor. The screen space ambient occlusion texture on the left has fewer details and lighter shadows than the ray-traced ambient occlusion texture on the right.

Follow these steps:

1. Enable screen space ambient occlusion.

2. Set up ray tracing in your HDRP project.

3. Select the GameObject with the volume override you created in step 1.

4. In the Inspector window of the Screen Space Ambient Occlusion override, enable Ray Tracing.

To control the effect, refer to the Ray-traced properties on the Ambient occlusion reference page.

To troubleshoot ray-traced ambient occlusion, HDRP provides an Ambient Occlusion Debug Mode and a Ray Tracing Acceleration Structure Debug Mode in Lighting Full Screen Debug Mode.

Additional resources

• Assign an ambient occlusion texture for each GameObject.
• Screen space ambient occlusion (SSAO), which uses information from the whole screen.