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The plastic material with the rough diffusing surface can be modeled in
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TracePro, but as two separate properties (select Define/EditPropertyData). `-\ "p;Hp0
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MATERIAL PROPERTY i=T/}c)
A TracePro Material Property can be created, and the index of refraction of 1P_bG47
the material is entered here, as well as an absorption coefficient if it is 3 !L)7Z/
known (this would be for absorption losses just from propogating through a 48`<{|r{
given thickness of a clear polished sample of the material, unrelated to the $@j7VPE
diffusing surface finish. Entering zero for the absorption coefficient is BoqW;SG $9
propobly a reasonable estimate for a transparent material. ;4IP7 $3G
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The Material Property is applied to the Object (Define/Apply Properties). =I1@ O9}+i
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SURFACE PROPERTY d6VKUAk'7>
A TracePro Surface Property can specify 5 possible outcomes for light incident Dr:}k*
on a surface - Specular Transmission, Specular Reflection, Scattered H>]x<#uz)
Transmission (BTDF). Scattered Reflection (BRDF), and Absorption. vrGNiGIi[
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For your property, I expect that Specular Transmission, Specular Reflection, w[ngkLEA
and Absorption would all be 0, leaving only Scattered Transmission (BTDF). 10&A3C(E
Scattered Reflection (BRDF). BTDF and BRDF are controlled by 3 coefficients - Zn/ /u<D
A, B, and g. For an initial estimate, I would suggest entering BTDF(g) = < ]nI)W(
BRDF(g) = 0, which defines a Lambertian dsitribution. hl+Yr)0\
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The challenge is to determine the proper ratio of Transmittance vs =`U[{3A_
Reflectance. You can enter a value for BRDF(A) and then use the Solve For W8^gPW*c5
feature to solve for BTDF, and the editor will display the resulting eC-TZ H@
Integrated BTDF and Integrated BRDF values. You want these to sum to 1, and {65X37W
to have a ratio that matches the behavior of your surface. If the ratio of T ? 6l::M
vs R is dependent on the Incidence Angle, you can use the Add button in the $j/F7.S
property to add Incidence ANgles to the table, and then define the BTDF and wS K?mS6
BRDF separately for each incidence angle.
