Solution: \Bf{/r5x
The plastic material with the rough diffusing surface can be modeled in #`EMK
TracePro, but as two separate properties (select Define/EditPropertyData). )v.FAV:
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MATERIAL PROPERTY #-8/|_*
A TracePro Material Property can be created, and the index of refraction of /;J;,G`?
the material is entered here, as well as an absorption coefficient if it is AS39 8L
known (this would be for absorption losses just from propogating through a .-
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given thickness of a clear polished sample of the material, unrelated to the q\G@Nn^
diffusing surface finish. Entering zero for the absorption coefficient is F U%b"gP^
propobly a reasonable estimate for a transparent material. =Ih_[$1dw
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The Material Property is applied to the Object (Define/Apply Properties). !h;VdCCi#
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SURFACE PROPERTY @:8|tJu8b
A TracePro Surface Property can specify 5 possible outcomes for light incident e&kg[jU
on a surface - Specular Transmission, Specular Reflection, Scattered &'j77tqOk
Transmission (BTDF). Scattered Reflection (BRDF), and Absorption. <aS1 bQgaU
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For your property, I expect that Specular Transmission, Specular Reflection, -A~<IyPt
and Absorption would all be 0, leaving only Scattered Transmission (BTDF). 9)`wd&!
Scattered Reflection (BRDF). BTDF and BRDF are controlled by 3 coefficients - ?J
AzN
A, B, and g. For an initial estimate, I would suggest entering BTDF(g) = nfU}ECun4
BRDF(g) = 0, which defines a Lambertian dsitribution. 37DvI&
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The challenge is to determine the proper ratio of Transmittance vs MDZb|1.AT
Reflectance. You can enter a value for BRDF(A) and then use the Solve For W*#/@/5
feature to solve for BTDF, and the editor will display the resulting \(s ";@
Integrated BTDF and Integrated BRDF values. You want these to sum to 1, and f&J*(F*u
to have a ratio that matches the behavior of your surface. If the ratio of T $MR4jnTT
vs R is dependent on the Incidence Angle, you can use the Add button in the Xb {y*',
property to add Incidence ANgles to the table, and then define the BTDF and [o "@*kf
BRDF separately for each incidence angle.
