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The plastic material with the rough diffusing surface can be modeled in wR/i+,K
TracePro, but as two separate properties (select Define/EditPropertyData). ?#D@e5Wf
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MATERIAL PROPERTY 4Df TVO"h
A TracePro Material Property can be created, and the index of refraction of lLtC9:
the material is entered here, as well as an absorption coefficient if it is VkhK2
known (this would be for absorption losses just from propogating through a xyz-T1ib
given thickness of a clear polished sample of the material, unrelated to the O,JthlAV4
diffusing surface finish. Entering zero for the absorption coefficient is +U%lWE%
propobly a reasonable estimate for a transparent material. Zml9 ndzT
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The Material Property is applied to the Object (Define/Apply Properties). #>ci!4Gz=Z
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SURFACE PROPERTY S_2I8G^A
A TracePro Surface Property can specify 5 possible outcomes for light incident %v~j1 0e
on a surface - Specular Transmission, Specular Reflection, Scattered x_Ais&Gc
Transmission (BTDF). Scattered Reflection (BRDF), and Absorption. iJrscy-
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For your property, I expect that Specular Transmission, Specular Reflection, >cM U<'&
and Absorption would all be 0, leaving only Scattered Transmission (BTDF). p dnL~sv
Scattered Reflection (BRDF). BTDF and BRDF are controlled by 3 coefficients - ^#^ u90I
A, B, and g. For an initial estimate, I would suggest entering BTDF(g) = ^ad>
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BRDF(g) = 0, which defines a Lambertian dsitribution. =AcbX _[
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The challenge is to determine the proper ratio of Transmittance vs 9y] $c1
Reflectance. You can enter a value for BRDF(A) and then use the Solve For //Tr=!TQu
feature to solve for BTDF, and the editor will display the resulting xI:;%5{L N
Integrated BTDF and Integrated BRDF values. You want these to sum to 1, and EUna_ 4=
to have a ratio that matches the behavior of your surface. If the ratio of T
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vs R is dependent on the Incidence Angle, you can use the Add button in the aeBth {
property to add Incidence ANgles to the table, and then define the BTDF and V` fh,(:
BRDF separately for each incidence angle.
