Solution: LHCsk{3
The plastic material with the rough diffusing surface can be modeled in Xt/Ksw"wn
TracePro, but as two separate properties (select Define/EditPropertyData). .
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MATERIAL PROPERTY K<sC F[
A TracePro Material Property can be created, and the index of refraction of !eR3@%4
the material is entered here, as well as an absorption coefficient if it is m4w ') r~
known (this would be for absorption losses just from propogating through a &a)eJF]:!
given thickness of a clear polished sample of the material, unrelated to the P,pnga3Wu
diffusing surface finish. Entering zero for the absorption coefficient is ~,6b_ W p/
propobly a reasonable estimate for a transparent material. 10[Jl5+t
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The Material Property is applied to the Object (Define/Apply Properties). Z,7R;,qX
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SURFACE PROPERTY DC+wD
Bp;
A TracePro Surface Property can specify 5 possible outcomes for light incident F N[R(SLbL
on a surface - Specular Transmission, Specular Reflection, Scattered - <_$m6x"A
Transmission (BTDF). Scattered Reflection (BRDF), and Absorption. 's
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For your property, I expect that Specular Transmission, Specular Reflection, KU9Z"9#
and Absorption would all be 0, leaving only Scattered Transmission (BTDF). Xk mQBV"
Scattered Reflection (BRDF). BTDF and BRDF are controlled by 3 coefficients - NmIHYN3
A, B, and g. For an initial estimate, I would suggest entering BTDF(g) = ,1{Ep`
BRDF(g) = 0, which defines a Lambertian dsitribution. h&@R| N
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The challenge is to determine the proper ratio of Transmittance vs uwIc963
Reflectance. You can enter a value for BRDF(A) and then use the Solve For V,v[y\
feature to solve for BTDF, and the editor will display the resulting #.B"q:CW*P
Integrated BTDF and Integrated BRDF values. You want these to sum to 1, and XEM'}+d
to have a ratio that matches the behavior of your surface. If the ratio of T ,3DXFV'uxb
vs R is dependent on the Incidence Angle, you can use the Add button in the 9Mm!%Hu
property to add Incidence ANgles to the table, and then define the BTDF and &F$:Q:* *
BRDF separately for each incidence angle.
