Solution: KPTp91
The plastic material with the rough diffusing surface can be modeled in j6}/pe*;;T
TracePro, but as two separate properties (select Define/EditPropertyData). r2"B" %;
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MATERIAL PROPERTY @'P\c
A TracePro Material Property can be created, and the index of refraction of a*/%EP3
the material is entered here, as well as an absorption coefficient if it is ^26 vP7
known (this would be for absorption losses just from propogating through a e*K1";
given thickness of a clear polished sample of the material, unrelated to the Ls51U 7
diffusing surface finish. Entering zero for the absorption coefficient is !X5n'1&
propobly a reasonable estimate for a transparent material. I 8M^]+c
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The Material Property is applied to the Object (Define/Apply Properties). _=$:<wIE[
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SURFACE PROPERTY IHC
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A TracePro Surface Property can specify 5 possible outcomes for light incident GE?M. '!{{
on a surface - Specular Transmission, Specular Reflection, Scattered `?P)RS30
Transmission (BTDF). Scattered Reflection (BRDF), and Absorption. 4}&$s
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For your property, I expect that Specular Transmission, Specular Reflection, )a99@`L\P
and Absorption would all be 0, leaving only Scattered Transmission (BTDF). 'z\$.L
Scattered Reflection (BRDF). BTDF and BRDF are controlled by 3 coefficients - }*Z *wC
A, B, and g. For an initial estimate, I would suggest entering BTDF(g) = z"D'rHxy
BRDF(g) = 0, which defines a Lambertian dsitribution. s&.VU|=VQ@
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The challenge is to determine the proper ratio of Transmittance vs 3pU/Z bb,:
Reflectance. You can enter a value for BRDF(A) and then use the Solve For Xlg 0u.
feature to solve for BTDF, and the editor will display the resulting :^b jn3b
Integrated BTDF and Integrated BRDF values. You want these to sum to 1, and ?azi(ja
to have a ratio that matches the behavior of your surface. If the ratio of T s[2 >r#M
vs R is dependent on the Incidence Angle, you can use the Add button in the uz
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property to add Incidence ANgles to the table, and then define the BTDF and 0[L)`7
BRDF separately for each incidence angle.
