Solution: CiF bk&-g
The plastic material with the rough diffusing surface can be modeled in bZJiubBRI
TracePro, but as two separate properties (select Define/EditPropertyData). 5lbh
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MATERIAL PROPERTY eIl&=gZ6>
A TracePro Material Property can be created, and the index of refraction of 1uE[ %M
the material is entered here, as well as an absorption coefficient if it is _l<"Qqt
known (this would be for absorption losses just from propogating through a 7dIDKx
given thickness of a clear polished sample of the material, unrelated to the ~*Wb MA
diffusing surface finish. Entering zero for the absorption coefficient is S([De"y
propobly a reasonable estimate for a transparent material. z@}~2K
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The Material Property is applied to the Object (Define/Apply Properties). P'';F}NwfX
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SURFACE PROPERTY b1"wQM9
A TracePro Surface Property can specify 5 possible outcomes for light incident ,.B8hr@H6-
on a surface - Specular Transmission, Specular Reflection, Scattered s,= ^V/c
Transmission (BTDF). Scattered Reflection (BRDF), and Absorption. 6w#v,RDEu
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For your property, I expect that Specular Transmission, Specular Reflection, Adm`s .
and Absorption would all be 0, leaving only Scattered Transmission (BTDF). k2a^g CBC
Scattered Reflection (BRDF). BTDF and BRDF are controlled by 3 coefficients - u^$ CR
A, B, and g. For an initial estimate, I would suggest entering BTDF(g) = rL/+`H
BRDF(g) = 0, which defines a Lambertian dsitribution. 3]Mx,u
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The challenge is to determine the proper ratio of Transmittance vs }M@ pdE
Reflectance. You can enter a value for BRDF(A) and then use the Solve For "k/x+%!Spc
feature to solve for BTDF, and the editor will display the resulting *@Z'{V\
Integrated BTDF and Integrated BRDF values. You want these to sum to 1, and dEn hNPeRl
to have a ratio that matches the behavior of your surface. If the ratio of T Hqk2W*UTl
vs R is dependent on the Incidence Angle, you can use the Add button in the ?T"crX
property to add Incidence ANgles to the table, and then define the BTDF and |k0V Ji
BRDF separately for each incidence angle.
