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The plastic material with the rough diffusing surface can be modeled in 99G/ (Z}
TracePro, but as two separate properties (select Define/EditPropertyData). .
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MATERIAL PROPERTY 2$yKa5SaX
A TracePro Material Property can be created, and the index of refraction of Sq/M
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the material is entered here, as well as an absorption coefficient if it is 91E!4t}I
known (this would be for absorption losses just from propogating through a U|g4t=@ZR
given thickness of a clear polished sample of the material, unrelated to the I|m fr{
diffusing surface finish. Entering zero for the absorption coefficient is 5ap}( bO
propobly a reasonable estimate for a transparent material. g~h`wv '
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The Material Property is applied to the Object (Define/Apply Properties). }C"EkT!F
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SURFACE PROPERTY 8^\DQ& D
A TracePro Surface Property can specify 5 possible outcomes for light incident &.an-
on a surface - Specular Transmission, Specular Reflection, Scattered 0?BT*
Transmission (BTDF). Scattered Reflection (BRDF), and Absorption. |iLeOztuE
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For your property, I expect that Specular Transmission, Specular Reflection, S"CsY2;
and Absorption would all be 0, leaving only Scattered Transmission (BTDF). 37?%xQ!
Scattered Reflection (BRDF). BTDF and BRDF are controlled by 3 coefficients - P-K\)65{Y
A, B, and g. For an initial estimate, I would suggest entering BTDF(g) = FgE6j;
BRDF(g) = 0, which defines a Lambertian dsitribution. PQWo<Uet
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The challenge is to determine the proper ratio of Transmittance vs _:+W0YS
Reflectance. You can enter a value for BRDF(A) and then use the Solve For ^T Vica
feature to solve for BTDF, and the editor will display the resulting qeQTW@6
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Integrated BTDF and Integrated BRDF values. You want these to sum to 1, and .Z xSJ"Rk
to have a ratio that matches the behavior of your surface. If the ratio of T G2ZF `WQ
vs R is dependent on the Incidence Angle, you can use the Add button in the &?9p\oY[
property to add Incidence ANgles to the table, and then define the BTDF and `XP ]y=
BRDF separately for each incidence angle.
