Adaptive Probe Volumes (APV)
The following is intended for informational purposes only, and may not be incorporated into any contract. No purchasing decisions should be made based on the following materials. Unity is not committing to deliver any functionality, features or code. The development, timing and release of all products, functionality and features are at the sole discretion of Unity, and are subject to change.
If you have accepted to use functional cookies and logged in using your Unity ID at the top right of the page, then sharing feedback is as simple as clicking a card below, selecting a topic’s importance, adding your point of view, and submitting. If you prefer not to accept functional cookies or log in, you will be prompted to enter an email address and validate it, so we know how to reach out when the topic evolves. For more information read the Feedback and privacy terms.
With the 2023.1 release, we have enabled the core functionality and user experience of Adaptive Probe Volumes in URP.
What are the benefits of Adaptive Probe Volumes?
For achieving a compelling visual experience through performant baked global illumination at runtime, Adaptive Probe Volumes enhance Unity’s existing capability of indirect lighting through Light Probes with these main benefits:
- Place Light Probes more easily through adaptive probe distribution
- Iterate faster as Light Probes density adapts to the updated geometry in scene
- Improved image quality with APV as compared to legacy Light Probes
- Light Probes can affect the indirect lighting of static objects in some scenarios
- Light Probe data streaming from the CPU to the GPU
Limitations of APV in URP with the 2023.1 Beta Release
Here is a summary of known limitations with the 2023.1 Beta Release:
- No Lightmap Scenario Blending
- No Lighting Normalization for Reflection Probes
- Performance may not yet be optimized, especially on lower-end mobile platforms
Summary
Adaptive Probe Volume (APV) is an improved workflow for pre-computed probe-based global illumination for 3D objects as a replacement for the existing Light Probe and Light Probe Proxy Volume (LPPV) systems in Unity.
Usecase/Intended Outcome
The probe placement workflow using the current Light Probe system is often tedious. It requires manual workflows and artist/developer intervention for set up and configuration to achieve quality results. The APVs improve on the existing probe system with an automatic probe placement workflow. ProbeVolumes are simple boxes that contain an adaptive 3D grid volume of probes, with the density of probes being configurable for each axis.
In the existing Light Probe system, a 3D Renderer receives lighting from a single Light Probe interpolated between the surrounding Light Probes in the Scene. Because of this, 3D objects have constant ambient lighting across the surface. This is especially noticeable on larger 3D objects or Particle Systems. With the APVs, probes in a volume are interpolated per-pixel rather than per object. This is similar to the existing LPPV system. However, APVs benefit from a much better workflow as compared to the LPPVs.
(The image above uses assets from ArchVizPro Interior Vol.7 HDRP from the Unity Asset Store.)