Solution: NK|UeL7ght
The plastic material with the rough diffusing surface can be modeled in ^s)`UZ<C=
TracePro, but as two separate properties (select Define/EditPropertyData). ;!<}oZp{
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MATERIAL PROPERTY 53t_#Y te
A TracePro Material Property can be created, and the index of refraction of NQ{(G8x9
the material is entered here, as well as an absorption coefficient if it is vF^d40gV
known (this would be for absorption losses just from propogating through a + M"j#H
given thickness of a clear polished sample of the material, unrelated to the ~0MpB~ {xd
diffusing surface finish. Entering zero for the absorption coefficient is
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propobly a reasonable estimate for a transparent material. `7/(sX.
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The Material Property is applied to the Object (Define/Apply Properties). XIwJhsYZ'9
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SURFACE PROPERTY QFP9"FM5F
A TracePro Surface Property can specify 5 possible outcomes for light incident kcfT|@:MK"
on a surface - Specular Transmission, Specular Reflection, Scattered 6b|<$Je9
Transmission (BTDF). Scattered Reflection (BRDF), and Absorption. j [U#J
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For your property, I expect that Specular Transmission, Specular Reflection, >.meecE?Q
and Absorption would all be 0, leaving only Scattered Transmission (BTDF). B=0^Rysg
Scattered Reflection (BRDF). BTDF and BRDF are controlled by 3 coefficients - kqBZsfF
A, B, and g. For an initial estimate, I would suggest entering BTDF(g) = ~i|6F~%3
BRDF(g) = 0, which defines a Lambertian dsitribution. $toTMah
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The challenge is to determine the proper ratio of Transmittance vs "\wM s
Reflectance. You can enter a value for BRDF(A) and then use the Solve For X%yG{\6:
feature to solve for BTDF, and the editor will display the resulting !|[rh,e]
Integrated BTDF and Integrated BRDF values. You want these to sum to 1, and sF{~7IB
to have a ratio that matches the behavior of your surface. If the ratio of T S= 4o@3%$
vs R is dependent on the Incidence Angle, you can use the Add button in the Y-ao
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property to add Incidence ANgles to the table, and then define the BTDF and :a }](Wn
BRDF separately for each incidence angle.
