Solution: VOKZ dC-
The plastic material with the rough diffusing surface can be modeled in R#xCkl -
TracePro, but as two separate properties (select Define/EditPropertyData). x N=i]~
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MATERIAL PROPERTY &yGaCq;0
A TracePro Material Property can be created, and the index of refraction of E>&n.%
the material is entered here, as well as an absorption coefficient if it is K2 he4<
known (this would be for absorption losses just from propogating through a D Gr>
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given thickness of a clear polished sample of the material, unrelated to the 4Yxo~ m(
diffusing surface finish. Entering zero for the absorption coefficient is wDcj,:h`
propobly a reasonable estimate for a transparent material. s<*XN NE7
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The Material Property is applied to the Object (Define/Apply Properties). _Bj)r}~7#
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SURFACE PROPERTY q:l>O5
A TracePro Surface Property can specify 5 possible outcomes for light incident )_1zRT| 9
on a surface - Specular Transmission, Specular Reflection, Scattered =6woWlf b
Transmission (BTDF). Scattered Reflection (BRDF), and Absorption. c#a @n 4
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For your property, I expect that Specular Transmission, Specular Reflection, 7Ok;Lt!x
and Absorption would all be 0, leaving only Scattered Transmission (BTDF). g1XZ5P} f
Scattered Reflection (BRDF). BTDF and BRDF are controlled by 3 coefficients - [ OHxonU
A, B, and g. For an initial estimate, I would suggest entering BTDF(g) = "vXxv'0 \f
BRDF(g) = 0, which defines a Lambertian dsitribution. 8S>&WR%jH]
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The challenge is to determine the proper ratio of Transmittance vs I'PeN0 T
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Reflectance. You can enter a value for BRDF(A) and then use the Solve For z."a.>fPaO
feature to solve for BTDF, and the editor will display the resulting /[O( ea$U
Integrated BTDF and Integrated BRDF values. You want these to sum to 1, and .^N/peU q
to have a ratio that matches the behavior of your surface. If the ratio of T g$HwxA9Gp/
vs R is dependent on the Incidence Angle, you can use the Add button in the A~Y^V En
property to add Incidence ANgles to the table, and then define the BTDF and D<|qaHB=
BRDF separately for each incidence angle.
