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The plastic material with the rough diffusing surface can be modeled in t<Acq07
TracePro, but as two separate properties (select Define/EditPropertyData). Hx gC*-A$/
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MATERIAL PROPERTY $NVVurXa
A TracePro Material Property can be created, and the index of refraction of j9h/`Bn
the material is entered here, as well as an absorption coefficient if it is $ ZI ]
known (this would be for absorption losses just from propogating through a xvOz*vM?
given thickness of a clear polished sample of the material, unrelated to the RK!9(^Ja
diffusing surface finish. Entering zero for the absorption coefficient is '. "_TEIF
propobly a reasonable estimate for a transparent material. x fb .Z(
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The Material Property is applied to the Object (Define/Apply Properties). a y oC]rE
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SURFACE PROPERTY X
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A TracePro Surface Property can specify 5 possible outcomes for light incident 5IF5R#
on a surface - Specular Transmission, Specular Reflection, Scattered KH Ac!4lA
Transmission (BTDF). Scattered Reflection (BRDF), and Absorption. _Xd"'cXw
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For your property, I expect that Specular Transmission, Specular Reflection, D -tRy~}
and Absorption would all be 0, leaving only Scattered Transmission (BTDF). K KB+o)*W
Scattered Reflection (BRDF). BTDF and BRDF are controlled by 3 coefficients - [q?RJm B]
A, B, and g. For an initial estimate, I would suggest entering BTDF(g) = 9w=7A>.U
BRDF(g) = 0, which defines a Lambertian dsitribution. Ah2 {kK
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The challenge is to determine the proper ratio of Transmittance vs V;%ug'j
Reflectance. You can enter a value for BRDF(A) and then use the Solve For N\PdX$
feature to solve for BTDF, and the editor will display the resulting r'*$'QY-N
Integrated BTDF and Integrated BRDF values. You want these to sum to 1, and /i,n75/y?
to have a ratio that matches the behavior of your surface. If the ratio of T ZHNL ~=r}
vs R is dependent on the Incidence Angle, you can use the Add button in the
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property to add Incidence ANgles to the table, and then define the BTDF and %hSQ\T<8[o
BRDF separately for each incidence angle.
