Daeshawn opened this issue on Mar 31, 2009 ยท 78 posts
bagginsbill posted Fri, 13 November 2009 at 6:30 AM
That .47 value for Gold came from the BlenderArtists forum and it's wrong.
All metals have IOR above 50!!
In Grapes, enter a=50 and see what the red (real Fresnel) curve does. It becomes highly reflective at all angles. This is why metals are metals - they have a very high IOR. Some are above 100.
[Edit] The subject of IOR for dialectrics is simple, but for metals, it gets complex, literally. Meaning, the IOR is a complex number involving a real part and an imaginary part.
In practice, the reflectivity of metals based on viewing angle is nearly constant, and does not really need a Fresnel effect to be convincing.
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