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Thread: MILA and the mystery "more accurate glossy reflection model"

  1. #1
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    Default MILA and the mystery "more accurate glossy reflection model"

    MILA documentation says glossy reflections use a "more accurate" shading model.

    So, I am trying to pin down what this "more accurate" shading model is based on.

    Typically a shading model takes on the name if its inventor. For instance, Ward, Phong, Blinn, Lambert.

    Is it safe to assume that this new model is proprietary (fine by me)? Or am I just not understanding MILA correctly.

  2. #2
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    They don't usually like to say because it may change over time as something "more accurate" happens to come along. But since there was a change early on to correct darkened edges, probably safe to say it's a proprietary/mixture of some sort.

    Unless one of the devs would want to explain more what this mix is.

    Is there a pressing reason you need to know what the combination is?
    "Don't argue with an idiot, they will drag you down to their level and beat you over the head with experience."

  3. #3
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    I have a new understanding of how MILA compares to named shaders (BLINN, PHONG, etc). Where as named shaders used combinations of glossy and diffuse lobes, MILA lets you define each lobe separately.

    Measured BSDF data from real world materials have multiple lobes for light response. While measured data is accurate, it is also expensive, time consuming, and data intensive to manage. Additionally, even if you have a ton of measured BSDF data, you still need to add spatial qualities to it. (Measured data is very clean). Things like chips in paint, scratches, and other natural effects that measured BSDF aren't really meant to capture in small scale. Having said that, someday measured BSDF will be more available; a good starting point for many shaders. NVIDIA has even detailed a file format specification for its recording. (MBSDF file format)

    http://www.nvidia-arc.com/fileadmin/..._11Jun2014.pdf

    Back to MILA - because we, for the most part, don't have measured BSDF data, we must rely on a shader artist to get the right combination of lobes to approximate how a material behaves to light. MILA shaders allow the custom lobes to be added together - much more powerful than just a layered shader.

    I needed to know because a MR rendered image was being compared to a DIRSIG rendered image. DIRSIG (www.DIRSIG.org) was using a Beard-Maxwell BRDF based material. It's really hard to make an apples to apples comparison though.

    Let me know if I am on the right track in my thinking.

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