Solution: aY6F4,7/B
The plastic material with the rough diffusing surface can be modeled in /a 6i`
TracePro, but as two separate properties (select Define/EditPropertyData). u*rHKZ9i
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MATERIAL PROPERTY .8;0O
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A TracePro Material Property can be created, and the index of refraction of cI rc@
the material is entered here, as well as an absorption coefficient if it is dfZ`M^NU
known (this would be for absorption losses just from propogating through a 7 y$a=+D i
given thickness of a clear polished sample of the material, unrelated to the U~ M!T#\s
diffusing surface finish. Entering zero for the absorption coefficient is tZu1jBO_Q4
propobly a reasonable estimate for a transparent material. `}rk1rl6
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The Material Property is applied to the Object (Define/Apply Properties). iJCv+p_f
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SURFACE PROPERTY Zq5~M bldh
A TracePro Surface Property can specify 5 possible outcomes for light incident )CgH|z:=b
on a surface - Specular Transmission, Specular Reflection, Scattered wxT( ktE
Transmission (BTDF). Scattered Reflection (BRDF), and Absorption. ^MG"n7)X
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For your property, I expect that Specular Transmission, Specular Reflection, QGE0pWL-a
and Absorption would all be 0, leaving only Scattered Transmission (BTDF). g${k8.T V
Scattered Reflection (BRDF). BTDF and BRDF are controlled by 3 coefficients - b/
h#{'
A, B, and g. For an initial estimate, I would suggest entering BTDF(g) = O=^/58(m
BRDF(g) = 0, which defines a Lambertian dsitribution. g}L>k}I?!W
~qK/w0=j
The challenge is to determine the proper ratio of Transmittance vs kv;P2:"|
Reflectance. You can enter a value for BRDF(A) and then use the Solve For [ugr<[6
feature to solve for BTDF, and the editor will display the resulting G^eXJusOv
Integrated BTDF and Integrated BRDF values. You want these to sum to 1, and F07X9s44E
to have a ratio that matches the behavior of your surface. If the ratio of T }]JHY P\
vs R is dependent on the Incidence Angle, you can use the Add button in the ;WgUhA
;q
property to add Incidence ANgles to the table, and then define the BTDF and ~R50-O
BRDF separately for each incidence angle.
