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Modeling a closed room LC vs IR

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  • Modeling a closed room LC vs IR

    Hello,

    So far I've mainly been doing 'exterior' scenes - if you will - where I just have a VRayPlane, and one or more light sources. Now I started to experiment with 'internal' scenes and have a question.

    I placed a box - as a room - flipped it's normals so I can texture the inside and created this sink. There is 1 VRayLight in the scene, a sphere shaped light.

    In this first image, I use irradiance map as the main GI and QMC as secondary. The settings are mainly default. I turned up HSph to 50 and used the 'Medium' preset. Notice the dark blotches at the right surface inside the sink where it's in shadow.



    In this next image below, I used Light Cache as the main GI. Settings are mainly default (Subdivs 1000; Sample size 0.02; Num passes 4; Pre filter on: 10; Filter: Fixed; Filter size: 0.04)

    Notice the results are much cleaner, even the dark blotches disappeared where the irradiance map had it. However, this completely screws up the "geometry" (?) of the sink. Notice the edges of the sink, especially at the inside right. What the heck is that!?



    So my question is, what is better for interior scenes? Irradiance or Light Cache? Maybe Photon Map? (haven't tried that one) And why does the LC provide cleaner results even with default settings (as far as no dark splothes) but screws up the geometry at the edges? The model's edges are perfectly smooth - it's a NURBS surface - and even in the viewport or using scanline rendering, the edges are perfectly smooth.

    In this case I use the inside of a simple box as a room. Do I need more lights maybe? I thought that in real life it's possible to have only 1 light in a room - such as this scene - and I only used 1 light.

    I bought Chris Nichols' both excellent DVDs (a while back), but shame on me, I still can't find the solution. In his interior DVD he shows the setup of 1 scene, but he still uses a direct light - as the moon - shining through the window. But I don't have any windows and I don't wanna add more lights because I want to illustrate a darker scene, so I don't know what technique to apply here.

    Any thoughts?

    Thanks!
    =LES=

  • #2
    sometimes scenes with less light need more samples then scenes with alot more light. I believe Chris mentioned something like that, at least in his exterior DVD. Try raising your hemispherical samples to 100 and see if it improves.
    ____________________________________

    "Sometimes life leaves a hundred dollar bill on your dresser, and you don't realize until later that it's because it fu**ed you."

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    • #3
      LC on primary is for preview purposes only. It can't replace irrmap (in case you set subdivs to smth higer than 1k + small sample size + you have to play with prefiltering).

      So use Irrmap as primary + LC as secondary.
      I just can't seem to trust myself
      So what chance does that leave, for anyone else?
      ---------------------------------------------------------
      CG Artist

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      • #4
        Thanks for the replies guys! Yes, leaving the primary in IR and changing the secondary to LC helped. And Photon Map as the secondary seems to work even better!
        =LES=

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        • #5
          Photons - don't mess with em
          I just can't seem to trust myself
          So what chance does that leave, for anyone else?
          ---------------------------------------------------------
          CG Artist

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