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  • Exposure / Illumination of Interior Scene

    Hi,

    I am fairly new to V-ray and just working on my first interiors.

    This scene is a bedroom on a yacht, which has low ceilings, lots of dark wood and 3 small windows (each 60x40cm in a row just out of shot on the right)
    Using the physical camera (shutter speed 100 / F-number 8 / ISO 120) and VRay Sun for the natural night, I seem to need a multiplier of around 80 to get the desired amount of natural light in the scene (before any artificial light) and still don’t really get the appearance of the sun beaming in. This value seems high for the sun, but I guess it is because of the small windows.

    The only lighting that you see in this rendering is the VRay sun coming through the windows (all spot lights are turned off - you only see the emmissive material)

    My main issue is that to achieve a high enough exposure, white or close to white colours like the bed sheets become almost fully clamped out when using colour mapping, and all definition is lost. The burning obviously only gets worse when the artificial lights are turned on.

    I assume this is largely due to the highly contrasting colours of the dark wood reflecting little light and the whites reflecting a lot of light.

    1. How can I overcome this burning of the white areas, while maintaining a good illumination / exposure?
    2. Is it better to have an area light shining through from just outside the windows to achieve a bright sun beam effect?
    3. I am using spotlights at a very wide angle for the artificial ceiling lighting (which are turned off in the render below), is it maybe better to use small area lights instead, to imitate the spot lights, so that the light distributes more evenly?

    Hoping someone can offer some helpfor the above or any other advise to achieve a better render ;D

    Cheers, Jim


  • #2
    Re: Exposure / Illumination of Interior Scene

    Hello Jim,
    don't know whether it helps, but here's my two cents to your post:

    - First of all, it's a pretty nice rendering you did!
    - As fas as I know, there is no ISO 120 in reality. Commonly used film speeds are 100, 160, 200.
    - There is no 1/100 shutter speed on a regular camera, either. But there's 1/60 and 1/125
    - Did you go for a sky GI together with the sunlight system?
    - Is your model done in 1:1 scale?
    - Did you use RGB 255,255,255 for white colour? This would explain the huge bleeding effect. In reality we don't have plain white, so I never go over RGB 230,230,230.
    - You can control contrast and saturation values in the GI options menu, just give it a try!



    Cheers,
    matthias

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    • #3
      Re: Exposure / Illumination of Interior Scene

      Thanks Matthias.

      I wasn't using RGB 255 for the whites, but they were above 230, I've toned them down below 230 now which certainly helps with the burning.

      I have now tried using a slightly yellow rectangular light (placed outside the windows, which are just out of shot on the right) to immitate the natural light (GI and BG turned off), which seems to light the room better than my attempts with v-ray sun and sky; is this a viable option for realism ?? or should i use GI with a solid colour instead, and which colour is best to immiate sunlight?

      The following render is with my interior lights turned on. I think it's an improvement on the last but i'm still not that happy with the result.
      Also, i really want to get some bright sun shine patches reflecting in the scene.

      Any suggestions are very welcome!!






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      • #4
        Re: Exposure / Illumination of Interior Scene

        Nice,On your previous one, did you try decreasing your burn value in color mapping, to something like 0.3 or so?

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        • #5
          Re: Exposure / Illumination of Interior Scene

          No, I didn't really change that. I thought that clamping out colours above 0.3 would make a lot of things very dark, but i'll have a play with that and see what happens. thanks.

          ps, I'm now using HSV exponential, which seems to work ok. what does anyone else prefer?

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