Question HDRP sundisc/bloom intensity from 2019.4 to 2020.3

Hi,

Today I attempted to make the switch to Unity 2020.3.19f1, coming from 2019.4.0f1. Nearly everything went fine, but I'm running into an issue with the sundisc from my Physically Based Sky. For some reason, in 2020.3, using the exact same settings, the sundisc ends up way too bright (especially compared to what it looked like in 2019.4).

A comparison:

2019.4


2020.3


I could tweak multiple settings to reproduce similar visuals, but I'd like to know what's causing this. It doesn't seem to have to do with the bloom settings, seeing as the red glowing cube is about the same between the two versions. Reducing the directional light's diameter to a very low value causes the sun's bloom to flicker (as the size is now tiny).

Has anyone run into this before? I couldn't find any other posts about this. You end up with a similarly bright sun when you switch the Visual Environment in the sample scene from HDRI to PBS, which just seems incorrect?

 

It looks like the issue is caused by volumetric fog.
i have this issue when i upgrade from hdrp8 to hdrp10.
they changed the default value for volumetric fog.
you could choose to turn off volumetric fog in your directional light.
or
if you want volumetric fog ->click your scene Volume object -> find "fog" - find "Anisotropy" -> increase it to 0.5-0.8.
if you don't see "Anisotropy" option,click "Show Additional Properties" in the list of the button on top right of every volume override.
hope this could help.

 

Thanks for your reply! Unfortunately; no luck. Disabling volumetric fog/setting the anisotropy value of volumetric fog doesn't influence the amount of bloom in this case.

Disabling bloom altogether works of course, but something is causing the sun to be overly bright with the same bloom/directional light settings for both versions. With bloom disabled this becomes even more clear, as the sundisc effectively becomes a bright white circle with no falloff where the sundisc for 2019.4 does show some color and falloff (and is somewhat smaller in size).

EDIT:
I guess it has to do with this fix in 10.0.0 (from the changelog):

• Fix sun disk intensity

I suppose setting the bloom intensity/scatter to much lower values gives an acceptable result.. But going from 0.5 to the 0.001-0.01 range seems odd. Additionally, setting the 'Flare Tint' color to black has a massive impact as well (which is what it's set to in the sample scene, which uses an HDRI sky), but also induces the flickering issue when moving the camera. Makes sense as it's similar to just setting the size to 0.

 

No one from Unity with any input regarding this?

 

Hi, I have indeed. This doesn't explain the difference when using the same settings, though. But I suppose that actually is because of the change I mentioned above.

 

The rendering of the celestial body got changed in 2020 in a more physical correct way, that's why it appears to be much brighter than before. It was simply incorrect back then.