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Thread: HDRI Exposure Control ?

  1. #16
    Quote Originally Posted by RPSchmidt View Post
    This was EXACTLY what I was going to write in my original reply, but then figured the video talked about all of those settings, so I opted instead to make a suggestion on something that might have been related (glossy reflections) and show an example using the settings pretty much as described in the quoted post above.
    RPSchmidt and Asticles - regarding step D) you say "This gives you all the realism you need from the environment". But when I do this and set surface reflection options to "raytrace only" then the HDRI environment stops showing up in my specular indirect channel and this affects the overall look of the specular for me. Is it the same for you on your side?

    Thanks again for your help.
    Scott

    Cape Town, South Africa
    http://www.youtube.com/user/independentvfx

  2. #17
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    Quote Originally Posted by scott.newman.ct View Post
    @fishhead - Wow! The despike filter actually worked out really well. Its almost sorted out the problem completely and no need for changing the surface reflection type now. I just hope the de-spiking stays nice and even and constant for animations. Will have to run a test.

    I honestly cant begin to say how thankful I am for these forums. If it wasnt for the help of other Lightwavers on these forums I would have quit a long time ago.
    Glad It helped at least to a degree. Hope it works out for your animation! Keep us posted! :-)

  3. #18
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    Quote Originally Posted by scott.newman.ct View Post
    RPSchmidt and Asticles - regarding step D) you say "This gives you all the realism you need from the environment". But when I do this and set surface reflection options to "raytrace only" then the HDRI environment stops showing up in my specular indirect channel and this affects the overall look of the specular for me. Is it the same for you on your side?

    Thanks again for your help.
    This information should be now in the direct part, please check specular direct (I'm talking from memory because I'm not in at home)
    English is not my native language so please be patient.

    Salvador Ureņa
    http://urenasalvador.wixsite.com/portfolio

  4. #19
    So here are some screenshots of what I am experiencing.

    Top viewport is the full render, bottom viewport is displaying the specular indirect channel

    Click image for larger version. 

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    Scott

    Cape Town, South Africa
    http://www.youtube.com/user/independentvfx

  5. #20
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    Quote Originally Posted by scott.newman.ct View Post
    So here are some screenshots of what I am experiencing.

    Top viewport is the full render, bottom viewport is displaying the specular indirect channel

    Click image for larger version. 

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    Click image for larger version. 

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    Click image for larger version. 

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    Hmm this is interesting...

    Maybe I was wrong... have to investigate it.
    English is not my native language so please be patient.

    Salvador Ureņa
    http://urenasalvador.wixsite.com/portfolio

  6. #21
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    This is from the manual: "
    If you have backdrop sampling for both the environment light and Global Illumination, the backdrop will be sampled twice (once by each system) and the brightness will be doubled. Remember to disable MIS in radiosity and set surfaces to raytraced only"

    https://docs.lightwave3d.com/lw2019/...ironment-light

    Maybe what you have is double specular lighting.

    Regards
    Last edited by Asticles; 09-12-2019 at 01:21 AM.
    English is not my native language so please be patient.

    Salvador Ureņa
    http://urenasalvador.wixsite.com/portfolio

  7. #22
    Quote Originally Posted by Asticles View Post
    This is from the manual: "
    If you have backdrop sampling for both the environment light and Global Illumination, the backdrop will be sampled twice (once by each system) and the brightness will be doubled. Remember to disable MIS in radiosity and set surfaces to raytraced only"

    https://docs.lightwave3d.com/lw2019/...ironment-light

    Maybe what you have is double specular lighting.

    Regards
    I dont think so - from what I can tell in my screenshots, "sample backdrop" is unchecked and I cant see any MIS option under radiosity (by radiosity Im assuming the Global Illumination tab?).

    To me the following makes sense and describes what I am seeing: - If one selects "Raytrace + Backdrop" with GI enabled then the surface is rendered as a combination of illumination and reflection from these two sources, but if one selects "Raytrace Only" then the surface will only be made of raytraced illumination from geometry, the backdrop will only show up as a reflection but doesnt contribute towards illuminating or lighting a surface.

    I dont know how accurate that observation is in terms of being in line with the manual, but it seems to be what is happening in my scene.
    Scott

    Cape Town, South Africa
    http://www.youtube.com/user/independentvfx

  8. #23
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    Can you post an image with GI Sample backdrop enabled and without the environment light? Although this is a problem with the specular...

    Maybe you should compare in same conditions with another engine, just to check.
    English is not my native language so please be patient.

    Salvador Ureņa
    http://urenasalvador.wixsite.com/portfolio

  9. #24
    Quote Originally Posted by Asticles View Post
    Can you post an image with GI Sample backdrop enabled and without the environment light? Although this is a problem with the specular...

    Maybe you should compare in same conditions with another engine, just to check.
    Click image for larger version. 

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    This screenshot is with GI sample backdrop enabled, and Ive changed the light type to distant and set its value to 0 to make sure its not doing anything. This setup seems to only give me the specular indirect as the final render. The "direct" light from the sun in the HDRI isnt showing up.

    What do you mean by "compare in same conditions with another engine"? Do you mean another render engine - all I have is LW?
    Scott

    Cape Town, South Africa
    http://www.youtube.com/user/independentvfx

  10. #25
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    Quote Originally Posted by scott.newman.ct View Post
    Click image for larger version. 

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    This screenshot is with GI sample backdrop enabled, and Ive changed the light type to distant and set its value to 0 to make sure its not doing anything. This setup seems to only give me the specular indirect as the final render. The "direct" light from the sun in the HDRI isnt showing up.

    What do you mean by "compare in same conditions with another engine"? Do you mean another render engine - all I have is LW?
    You have forgot to enable isbg sampling.

    I want to compare the result with the Raytrace Only image that you posted before.

    About the other render engine, it was to compare with octane.
    Last edited by Asticles; 09-12-2019 at 05:12 AM.
    English is not my native language so please be patient.

    Salvador Ureņa
    http://urenasalvador.wixsite.com/portfolio

  11. #26
    Sure thing

    Here it is again with ISBG sampling enabled. When I enable the ISBG sampling box the only thing that changes is the white helmet of the pilot catches a highlight. For some reason the conductor material doesnt change at all.
    Click image for larger version. 

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    Scott

    Cape Town, South Africa
    http://www.youtube.com/user/independentvfx

  12. #27
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    How strange, isbg should deliver a better light distribution. Let's see if someone can give a clue about this.

    Have tested by myself, and environment with backdrop is delivering on my scene much less colors:

    Click image for larger version. 

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    But Environment light without backdrop...

    Click image for larger version. 

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    Edit: SSS is not working fine with light from the environment gi.
    Last edited by Asticles; 09-12-2019 at 08:34 AM.
    English is not my native language so please be patient.

    Salvador Ureņa
    http://urenasalvador.wixsite.com/portfolio

  13. #28
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    Without SSS, I think using the env light is still better....

    Click image for larger version. 

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    Than backdrop.

    Click image for larger version. 

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    English is not my native language so please be patient.

    Salvador Ureņa
    http://urenasalvador.wixsite.com/portfolio

  14. #29
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    Quote Originally Posted by scott.newman.ct View Post
    Sure thing

    Here it is again with ISBG sampling enabled. When I enable the ISBG sampling box the only thing that changes is the white helmet of the pilot catches a highlight. For some reason the conductor material doesnt change at all.
    Click image for larger version. 

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    Scott,

    If you haven't already, try going to the Image Editor and setting your HDRI image RGB and Alpha color spaces to Linear.

    Then please try the render again using Raytrace+Backdrop and Raytrace Only with the settings below and glossy reflections off (make sure you are changing the Raytrace settings for both Reflection and Refraction on your surfaces' shading model tab when you test, i.e., bot Reflection and Refraction are set to Raytrace Only, etc).

    Please also note; there is only light here, the environment light.

    Click image for larger version. 

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    In both instances, you should end up with the exact same render.

    This probably won't solve your issues, but I'm curious to see what you end up with.

    I also want to add, it is a truth that HDRI images will vary in their exposure; so far in my experience, the HDRIs I get are either perfectly exposed or underexposed.

    Typically, for underexposed HDRI images, I set the Gamma to 2.2. I don't really have to make any other adjustments.

    Give cloudy layers 4k from HDRI Haven a try (Cloudy Layers); set the colorspace to linear in the Image Editor, and the gamma to 2.2 and try my settings for camera, light, render, and GI.

  15. #30
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    I'm sorry if I haven't helped you so much.
    English is not my native language so please be patient.

    Salvador Ureņa
    http://urenasalvador.wixsite.com/portfolio

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