Adaptive Probe Volumes - Low resolution / Blobby shadows

[sweet jacinth]

Hello!

I'm implementing a day/night cycle for my game, and so I decided to try using Adaptive Probe Volumes, as they have the option to create different Lighting Scenarios.

The issue is, for this purpose I am forced to set all Mesh Renderers to Contribute Global Illumination and Receive Global Illumination from Light Probes.

When I do this, the resolution of all my shadows looks much worse, I keep seeing artifacts on larger surfaces and generally the quality is nothing compared to other showcases I've seen, that used Adaptive Probe Volumes. Why is that?

I tried fiddling with the Lighting>Scene options, but oddly enough, they don't seem to have much effect.

What settings are contributing to the quality of lighting with Adaptive Probe Volumes?
Is there some key setting in the Renderer Asset settings I should change (I noticed there is 'Adaptive Probe Volumes Options' in Volumes)?

The light I am using are fully baked (not using Mixed).

I'm including an image of the ugly shadows/blobs I keep seeing and the settings I use for baking, which I bumped up to prove they don't have much effect (I assume they are mostly related to Lightmapping, though).

Thank you for any tips

[rapid bay]

The accuracy of shadows and other sharp changes in lighting depends on the density of your probes, which is controlled by Min Probe Spacing

If that setting is not in the Adaptive Probe Volumes panel, I think it's in the APV component
*https://docs.unity3d.com/6000.1/Documentation/Manual/urp/probevolumes-changedensity.html

Capturing sharp shadows is always inefficient with baked lighting, both APVs and lightmaps, as it requires really high resolutions

Mixed lights are preferable whenever you need direct shadows

The patchy lighting in the solid surfaces mostly look like brick seams ("Fix seams"), but it could also be related to if your surfaces are made of multiple modular meshes

The walls especially near the base seem to be receiving wrong lighting, which is likely a light leak which the above link also talks about

Confirm which probes those spots are lit by using Rendering Debugger

I expect you'll find those spots are being lit by probes under the ground, which aren't being shadowed by anything
Typically I'd move those probes above ground / closest area where they receive valid lighting using probe adjustment volume virtual offset should fix them
Alternatively you can tweak virtual offset and dilation settings to automatically catch and eliminate lighting from incorrect locations

[sweet jacinth]

Thank you very much for such a detailed answer!

I tried playing with the Min Probe Spacing, but adjusting the location of the probe volume itself lead to the best improvement (as you suggested, many of the probes were incorrectly in/below the ground - in some cases parts of the level were omitted completely with large blind spots of nothing). Thank you for that!

The shadows are still not ideal, and I assume my only option will be to use Mixed lighting instead as you said.

In that case, I have a little bit of trouble visualising how to set up the Day/Night cycle. I currently use 4 groups of lights for each of the lighting scenarios (Morning, Noon, Afternoon, Night), which I use for baking and which use 'baked' Mode.
And on top of that, I should have copy of all these lights with 'Mixed' mode, which are controlled by a script and their color/intensity/position/rotation is somehow blended between the target states?

Or should I at runtime enable one of these 4 groups of 'Mixed' lights, and blend their intensities/colors alongside the Lighting Scenarios? And then have subgroups defined for light specific those conditions?

I'm only left wondering what the 'intended' way was behind the Lighting Scenarios.

[rapid bay]

I'm not sure either
There's this video that shows them using lighting scenarios with a moving sun, but haven't had time to dig into it
The sample scene is downloadable but I don't recall if it included the setups they use for these more specific examples
https://youtu.be/IpVuIZYFRg4?t=1909

[stable arch]

@sweet jacinth Hi - sorry to bump such an old thread, but I'm also trying to sort out a time-of-day system with APVs and I think I'm running into a similar issue.

I have two scenarios: A and B. A has a light pointing left, and B has one pointing right. When I bake one scenario, the other one updates to be identical to it, so blending does nothing. I can only fix this by swapping all renderers from 'Receive GI: Lightmaps' to 'Receive GI: Light Probes', but as you describe it causes all shadows to appear much lower resolution.

Did you learn any more about how this system is supposed to work? I couldn't find anything in the docs saying that we need to use 'Receive GI: Light Probes', and I was hoping to have smooth blending between two sets of high-resolution shadows.

[sweet jacinth]

Not much, I'm afraid. I believe I achieved the best results by using Mixed lighting in the end, though as of now I am working on parts that don't need, so I haven't used it much in practice.
What helped significantly at reducing any artefacts was making the volume fit more tightly and using the correct layers - I found excluding certain layers created far-too-large gaps in the probes. And you should account for the cubemaps, as they carry over the lighting of when they were baked.
Sorry I can't provide more details, I will share more insight once I eventually get to implementing and polishing the lighting later on.