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The plastic material with the rough diffusing surface can be modeled in * AsILK 0
TracePro, but as two separate properties (select Define/EditPropertyData). $MW-c*5a
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MATERIAL PROPERTY {7EnM1]
A TracePro Material Property can be created, and the index of refraction of ^7b[s pq E
the material is entered here, as well as an absorption coefficient if it is v67utI SNI
known (this would be for absorption losses just from propogating through a Cu2eMUGt
given thickness of a clear polished sample of the material, unrelated to the k@}?!V*l
diffusing surface finish. Entering zero for the absorption coefficient is R1,.H92
propobly a reasonable estimate for a transparent material. %w9/ gD
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The Material Property is applied to the Object (Define/Apply Properties). s,z$Vt"h*K
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SURFACE PROPERTY .>X 0 $#
A TracePro Surface Property can specify 5 possible outcomes for light incident 4c })LAwd&
on a surface - Specular Transmission, Specular Reflection, Scattered ~Qg:_ @@\
Transmission (BTDF). Scattered Reflection (BRDF), and Absorption. &\n<pXQ
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For your property, I expect that Specular Transmission, Specular Reflection, W#|30RU.G
and Absorption would all be 0, leaving only Scattered Transmission (BTDF). [nSlkl
Scattered Reflection (BRDF). BTDF and BRDF are controlled by 3 coefficients - .$ o0$`}
A, B, and g. For an initial estimate, I would suggest entering BTDF(g) = L>trLD1pt
BRDF(g) = 0, which defines a Lambertian dsitribution. R=7,F6.
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The challenge is to determine the proper ratio of Transmittance vs *8I+D>x
Reflectance. You can enter a value for BRDF(A) and then use the Solve For B|fh 4FNy
feature to solve for BTDF, and the editor will display the resulting $m
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Integrated BTDF and Integrated BRDF values. You want these to sum to 1, and &XvSAw+D@
to have a ratio that matches the behavior of your surface. If the ratio of T AiF'*!1
vs R is dependent on the Incidence Angle, you can use the Add button in the ejF GeR
property to add Incidence ANgles to the table, and then define the BTDF and jH 5VrN*Q
BRDF separately for each incidence angle.
