Understand the ambient light probe
HDRP uses the ambient Light Probe as the final fallback for indirect diffuse lighting. It affects:
- All Mesh Renderers if there is no indirect ambient light computed for the Scene (this applies when Unity has not computed any lightmaps or Light Probes for the Scene)
- Mesh Renderers that have their Light Probe Mode set to Off
- Volumetric fog if the Global Light Probe dimmer is set to a value above 0
The ambient Light Probe can be static (generated only once from the static lighting sky set in the HDRP **Environment (HDRP)**panel) or dynamic (updated at runtime from the sky currently in use).
*Note*: If there is a *Light Probe group* in your Scene and you have computed indirect ambient lighting, then the Ambient Light Probe only affects Mesh Renderers that have their *Light Probe Mode* set to *Off*, and that have *Volumetric fog* (if it’s enabled in the Scene).
Limitations of dynamic ambient mode
The Ambient Light Probe always affects your scene one frame late after HDRP calculates it. This is because HDRP calculates Ambient Light Probes on the GPU and then uses asynchronous readback on the CPU.
As a result, the ambient lighting might not match the actual lighting and cause visual artifacts. This can happen when you use the dynamic ambient mode and use reflection probes that update on demand.
Did you find this page useful? Please give it a rating:
Thanks for rating this page!
What kind of problem would you like to report?
Thanks for letting us know! This page has been marked for review based on your feedback.
If you have time, you can provide more information to help us fix the problem faster.
Provide more information
You've told us this page needs code samples. If you'd like to help us further, you could provide a code sample, or tell us about what kind of code sample you'd like to see:
You've told us there are code samples on this page which don't work. If you know how to fix it, or have something better we could use instead, please let us know:
You've told us there is information missing from this page. Please tell us more about what's missing:
You've told us there is incorrect information on this page. If you know what we should change to make it correct, please tell us:
You've told us this page has unclear or confusing information. Please tell us more about what you found unclear or confusing, or let us know how we could make it clearer:
You've told us there is a spelling or grammar error on this page. Please tell us what's wrong:
You've told us this page has a problem. Please tell us more about what's wrong:
Thank you for helping to make the Unity documentation better!
Your feedback has been submitted as a ticket for our documentation team to review.
We are not able to reply to every ticket submitted.