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Light probes not affecting object correctly

Discussion in 'Global Illumination' started by olejuer, Oct 8, 2020.

  1. olejuer

    olejuer

    Joined:
    Dec 1, 2014
    Posts:
    211
    Hi,

    I am trying to get light probes to work, but they don't act like I would expect.
    In a very simple test scene where the only light source is the skybox environment, I bake a lightmap and light probes. I have three test objects (see screenshot), one using blend probes (left), one using a static lightmap (middle), and one using neither (right). All use the same, plain, white material.
    The lightmap seems to be accurate, if full of artifacts.
    The blendprobes seem to be accurate, judging from the gizmos.
    The realtime lit objects, both with blend probes and without, are significantly darker than expected.

    I am using Unity 2020.1.6f1 and URP (settings in screenshot).
    Any idea why this behaves so different from what I would expect?

    upload_2020-10-8_12-53-43.png
     
  2. thefranke

    thefranke

    Unity Technologies

    Joined:
    Jun 20, 2015
    Posts:
    153
    Hey olejuer,

    are you using Gamma or Linear mode?

    Cheers
     
  3. olejuer

    olejuer

    Joined:
    Dec 1, 2014
    Posts:
    211
    Thank you! Indeed, I was using Gamma light mode and the problem does not occur in Linear mode. Would have taken me a while to pinpoint that.
    Is this behaviour to be expected in Gamma mode?

    Cheers
     
  4. thefranke

    thefranke

    Unity Technologies

    Joined:
    Jun 20, 2015
    Posts:
    153
    Instinctively I'd say no :D However, gamma mode is always a bit tricky. There are conversions going back and forth in many places (not just at the input and output), so bugs can creep in very easily. Do you need Gamma mode for your project, or is linear fine? I will try to find out what could be the cause in this scenario.
     
  5. olejuer

    olejuer

    Joined:
    Dec 1, 2014
    Posts:
    211
    Linear is actually better. So I think for my project I am good.
    To reproduce, a new URP project immediately has this issue. I can report a ticket if that helps. Otherwise thank you for your support!
     
    thefranke likes this.
  6. thefranke

    thefranke

    Unity Technologies

    Joined:
    Jun 20, 2015
    Posts:
    153
    If you have time, please make a ticket, otherwise I'll do it! Thank you!
     
  7. olejuer

    olejuer

    Joined:
    Dec 1, 2014
    Posts:
    211
    Done (Case 1285283)
     
    Last edited: Oct 15, 2020
    thefranke likes this.