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  • Question about Glass

    I've created a glass materail and am tweaking the settings for a more realistic look.

    To create the material, I've done the following:

    1) On the diffuse layer, I set the color to black. Where it says transparency on the right, I click the "m" and set the common type to fresnel. Leaving everything else as default.

    Test render 1 = Transparent material that looks a little cloudy and no reflections or object thickness.

    2) Create a reflection layer leaving its default settings.

    Test render 2 = almost a chrome or shiny metal surface.

    3) On the reflection layer, I clicked the "m" next to reflection and now for this layer, enabled frensel.

    Test render 3 = TR1

    4) Created a refraction layer and enabled frensel. Material preview shows decent glass.

    Test render 4 = Glass with a nice edge but a little too black on the edge and the transparency is a little dirty.

    5) Under options, I turned off double-sided.

    Test render 5 = A reflective glass edge and dirty glass.

    All the above tests have the glass floating just a hair above the surfaces it sits on. The following test shows what happens to the glass when I render it actually sitting on the objects.

    Test render 6 = Where the glass touches an object it renders pitch black. Note double-sided is not checked.

    Now, I added an emissive material to a portion of the stick. RGB is 63, 191, 127 and a multiplier of 2. The preview of this shows as purple glow.

    Test render 7 = is a blue light where not covered by the glass, and green where its under the glass.

    Now for my questions.

    TR7 - why is the emissve material changing colors?
    TR6 - why does glass render pure black when touch other objects?
    TR4 - I think this looks more real (when double sided is checked) for sheet glass.

    Q1 - How do I get the glass to not look so dirty?

    Any other comments on what you might see in this test i.e. opinions, suggestions etc are welcome.








  • #2
    Question about Glass

    Glass: delete the diffuse layer from the material, set the reflection map to fresnel and use the fraction layer like default. If you set the refraction color, than the glass is constant tinted, if you use the fog color, than you get a tint with attenuation effect. If you like to use colored shadow (caustic fake) than set "effect shadow". "Double side" or not? I don't know, try it.

    Black intersection artefacts: if two surfaces are at the same place, the engine dosn't know, which color should be used and it render black. But, if you use a bias, than it helps to avoid black intersections. If you intersect object of the same material, no artefact will be visible. In your case I would buildin a small gap.
    Bias option: if you use GI only, the general bias option is good enough. If you use additional lights, you must set a bias at the light properties. A start value could be 0.001.

    -Micha
    www.simulacrum.de - visualization for designer and architects

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    • #3
      Question about Glass

      You don't have to delete the diffuse layer entirely, just make sure it's transparency is not black ( if its black no light is reaching to any layers below it which means any refraction layers are essentially removed from the equation)
      Best regards,
      Joe Bacigalupa
      Developer

      Chaos Group

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      • #4
        Question about Glass

        @Micha - Thanks for the tips. These are good and I will try them.

        @Joe - For now, I tried your approach to solve my problem. My transparancey color on the diffure layer was indeed black. The easiest solution was to make this color pure white. So I did but my rendering was unchanged.

        Bill

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        • #5
          Question about Glass

          This time, I used Micha's technique. Here, my glass has the diffuse layer removed, the refraction layer is default. Micha, its "clear" - pun intended, that your approach works.

          Bill

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