Solution: C'CdVDm X
The plastic material with the rough diffusing surface can be modeled in ({p @Ay
TracePro, but as two separate properties (select Define/EditPropertyData). "AMsBvzgo
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MATERIAL PROPERTY -xc'P,`
A TracePro Material Property can be created, and the index of refraction of / S)&d N`
the material is entered here, as well as an absorption coefficient if it is aFwfF^\(|,
known (this would be for absorption losses just from propogating through a %dA7`7j
given thickness of a clear polished sample of the material, unrelated to the 0Kenyn4 ?
diffusing surface finish. Entering zero for the absorption coefficient is p4I6oS`/.
propobly a reasonable estimate for a transparent material. iC\t@BVS
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The Material Property is applied to the Object (Define/Apply Properties). <D{_q.`vA
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SURFACE PROPERTY O8S"B6?$~'
A TracePro Surface Property can specify 5 possible outcomes for light incident Y4n; [nHQ(
on a surface - Specular Transmission, Specular Reflection, Scattered pM7xnL4
Transmission (BTDF). Scattered Reflection (BRDF), and Absorption. U0%m*i
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For your property, I expect that Specular Transmission, Specular Reflection, [P"R+$"
and Absorption would all be 0, leaving only Scattered Transmission (BTDF). |p{FSS
Scattered Reflection (BRDF). BTDF and BRDF are controlled by 3 coefficients - 'aW<C>
A, B, and g. For an initial estimate, I would suggest entering BTDF(g) = oFUP `p%[
BRDF(g) = 0, which defines a Lambertian dsitribution. h` $2/%?
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The challenge is to determine the proper ratio of Transmittance vs Ok2>%e
Reflectance. You can enter a value for BRDF(A) and then use the Solve For 80qe5WC.2u
feature to solve for BTDF, and the editor will display the resulting I@9k+JB
Integrated BTDF and Integrated BRDF values. You want these to sum to 1, and 2d Px s:8&
to have a ratio that matches the behavior of your surface. If the ratio of T )x*pkE**c
vs R is dependent on the Incidence Angle, you can use the Add button in the bAqaf#}e
property to add Incidence ANgles to the table, and then define the BTDF and rC!~4xj-
BRDF separately for each incidence angle.
