How to make scene's Ambient (HDRP Ambient Probe) independent from Sky background?

Unity Engine
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1

I want simply set Ambient and Sky individually in scene.

From what I understand:
You cannot manually set Ambient Probe, you have to set Sky as ambient source in Visual Environment.
and HDRP camera always use Ambient from that Skybox & draw that Skybox as background.
Changing Sky background will change scene’s Ambient.
If I am wrong please tell me.

there is a piece of document :
[Decoupling the visual environment from the lighting environment]
https://docs.unity3d.com/Packages/com.unity.render-pipelines.high-definition@12.1/manual/Environment-Lighting.html

From the brief document above I can’t really see how to make it work.

I did tried different setup from the information I could get from the doc:

  1. assign Volume Objects to different Layer,
  2. select different Light Override Mask in HDRP Asset,
  3. change camera’s Volume mask/ Probe Layer mask
  4. change camera’s Layer

These does not work for me.

Any advise is appreciated, thank you.

2

Hi,

You can configure your ambient probe independent from your (camera) background sky by following these steps:

  1. Create two volume profiles, volume 1 will contain the visual environment with your camera background, and volume 2 will contain the environment used for your ambient probe

  1. Add volume profile 1 to an active GameObject in your scene (and for example, set mode to Global) so it will be used as your camera background

  1. Navigate to Window → Rendering → Lighting and set the “Profile” to volume profile 2 and select the correct “Static Lighting Sky”

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3

@m0nsky

Thanks for reply.

Just tried to follow the steps but unfortunately it is not working
Please see the setup in attachment

  1. All ambient modes are set to dynamic, and no lightmap is baked in lighting window

  2. Changing Gradient Sky color / Exposure in AmbientVolumeProfile does not seems to contribute to any change to lighting, which I can assume it does not override the SkyBackgroundVolumeProfile’s Ambient

8199024--1069329--scene.png
8199024--1069329--scene.png997×561 31.6 KB

8199024--1069326--hdrp.jpg
8199024--1069326--hdrp.jpg1000×1200 175 KB

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4

@virtualdruid70 If you set the “Ambient Mode” of the SkyBackgroundVolume in your scene to “Static”, the ambient probe will automatically switch to the sky setup configured in the environment lighting panel (GradientSky)

5

Changing either 1 or both Ambient mode to Static in these 2 Volume Profile doesn’t seems to work.
I’m using Unity version 2021.3.2f1+. I will try lower version.

8199102--1069365--h1.png
8199102--1069368--h1.png
8199102--1069371--h1.png

6

Just created an empty project with identical scene setup in Unity 2020.3.15f2 LTS.
Still not working tho.
I don’t think it’s the problem with version.

8200377--1069674--h4.png
8200377--1069677--h5.png
8200377--1069680--h5.png
8200377--1069683--h5.png

7

Hey, to help you out here and to extend on @ 's workflow. the system is working fine, you’re just missing a few things.

You can refer to monsky’s workflow as well.

Volume Profile Setup

-You can use a single volume to decouple or like monsky’s workflow use one for each, for this example, I’m just going to use one, you should decide that on a scene-by-scene basis as the need may differ.

-This can also apply to using HDRIs as the Ambient probe

-You can also use an HDRI to drive the ambient probe via physcially based sky too ( via Ground Colour Texture)

Ambient Probe

like the decouple doc states, you have to set the Visual environment > Ambient Probe to Static
and in the Lighting Environment window the environment profile your target volume with its sky override component.

That part differs whether you have the component on a
-separate volume ( a la monsky’s workflow)
-the same volume ( this workflow)
-on the Physically Based Sky component override (when set to static)

Exposure (the bit you missed)

Physically-based sky takes care of a lot of the colour and connective to the directional light and ambient probe, however, if you’re using a decoupled ambient probe you have to set the exposure on the component for the sky you’re using.
in this instance, my scene is exposed @11.4ev with PBS, so that’s also going to be my exposure compensation for gradient sky, this also mirrors what you would do if you were to use an HDRI sky instead.

Hope that helps

8200980--1069881--PBS GS exposure .jpg
8200980--1069884--PBS ambient probe gradient sky.gif
8200980--1069887--PBS vis and GS probe.jpg
8200980--1069890--PBS vis and probe.jpg

8

Thanks !
What I’m missing really is the Exposure Compensation.

Thanks for help, @m0nsky @HIBIKI_entertainment .
Much appreciated.

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