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The plastic material with the rough diffusing surface can be modeled in H zd tR
TracePro, but as two separate properties (select Define/EditPropertyData). FQc8j:'
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MATERIAL PROPERTY n*7Ytz3#'
A TracePro Material Property can be created, and the index of refraction of ; QVX'?
the material is entered here, as well as an absorption coefficient if it is pf_(?\oz>
known (this would be for absorption losses just from propogating through a .i^aYbB$X
given thickness of a clear polished sample of the material, unrelated to the U
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diffusing surface finish. Entering zero for the absorption coefficient is \Y V`M3O
propobly a reasonable estimate for a transparent material. JqX+vRY;dd
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The Material Property is applied to the Object (Define/Apply Properties). !F@9xG
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SURFACE PROPERTY (]wd8M
A TracePro Surface Property can specify 5 possible outcomes for light incident jrOqspv
on a surface - Specular Transmission, Specular Reflection, Scattered :fxG]uf-P
Transmission (BTDF). Scattered Reflection (BRDF), and Absorption. ;c ye
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For your property, I expect that Specular Transmission, Specular Reflection, fu}ZOPu
and Absorption would all be 0, leaving only Scattered Transmission (BTDF). 4tv}5llSG
Scattered Reflection (BRDF). BTDF and BRDF are controlled by 3 coefficients - 0vu$dxb[
A, B, and g. For an initial estimate, I would suggest entering BTDF(g) = O@$wU9 D<
BRDF(g) = 0, which defines a Lambertian dsitribution. ^xB=d S~
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The challenge is to determine the proper ratio of Transmittance vs F;I % 9-R
Reflectance. You can enter a value for BRDF(A) and then use the Solve For !R { C
feature to solve for BTDF, and the editor will display the resulting D7| =ev
Integrated BTDF and Integrated BRDF values. You want these to sum to 1, and vMDX
to have a ratio that matches the behavior of your surface. If the ratio of T _trF /U<
vs R is dependent on the Incidence Angle, you can use the Add button in the s]tBd !~
property to add Incidence ANgles to the table, and then define the BTDF and GS!7HphR
BRDF separately for each incidence angle.
