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The plastic material with the rough diffusing surface can be modeled in BD 6!,
TracePro, but as two separate properties (select Define/EditPropertyData). A#>wbHjWF
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MATERIAL PROPERTY =D zrM%
A TracePro Material Property can be created, and the index of refraction of l;$F[/3a
the material is entered here, as well as an absorption coefficient if it is N$=YL
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known (this would be for absorption losses just from propogating through a =^"Sx? ?V
given thickness of a clear polished sample of the material, unrelated to the f/\!=sa:
diffusing surface finish. Entering zero for the absorption coefficient is 8X;?fjl`"
propobly a reasonable estimate for a transparent material. lM-\: Q!
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The Material Property is applied to the Object (Define/Apply Properties). (>`_N%_
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SURFACE PROPERTY as07~Xvp-
A TracePro Surface Property can specify 5 possible outcomes for light incident $W._FAAJ#
on a surface - Specular Transmission, Specular Reflection, Scattered `&;#A *C0
Transmission (BTDF). Scattered Reflection (BRDF), and Absorption. q NGR6i
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For your property, I expect that Specular Transmission, Specular Reflection, '! >9j,BJ
and Absorption would all be 0, leaving only Scattered Transmission (BTDF). + o+f\!
Scattered Reflection (BRDF). BTDF and BRDF are controlled by 3 coefficients - He_ O+[sc
A, B, and g. For an initial estimate, I would suggest entering BTDF(g) = ]t[%.^5#
BRDF(g) = 0, which defines a Lambertian dsitribution. mQj# \<*
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The challenge is to determine the proper ratio of Transmittance vs sbvP1|P8%
Reflectance. You can enter a value for BRDF(A) and then use the Solve For >iyNZ]."\
feature to solve for BTDF, and the editor will display the resulting g}9 ,U&$]y
Integrated BTDF and Integrated BRDF values. You want these to sum to 1, and ft" -
to have a ratio that matches the behavior of your surface. If the ratio of T wXNng(M7
vs R is dependent on the Incidence Angle, you can use the Add button in the a$W
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property to add Incidence ANgles to the table, and then define the BTDF and o*T?f)_[p
BRDF separately for each incidence angle.
