Solution: Hd~g\
The plastic material with the rough diffusing surface can be modeled in 6!\V|
TracePro, but as two separate properties (select Define/EditPropertyData). D
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MATERIAL PROPERTY FRQ.ix2
A TracePro Material Property can be created, and the index of refraction of wL0[Slf}
the material is entered here, as well as an absorption coefficient if it is nwFBuP<LR
known (this would be for absorption losses just from propogating through a /vSGmW-*
given thickness of a clear polished sample of the material, unrelated to the JwSF}kNs}
diffusing surface finish. Entering zero for the absorption coefficient is D 6bYg `
propobly a reasonable estimate for a transparent material. \s)MN s
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The Material Property is applied to the Object (Define/Apply Properties). :h(HKMSk1
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SURFACE PROPERTY X:W\E eH
A TracePro Surface Property can specify 5 possible outcomes for light incident xS|9Gk
on a surface - Specular Transmission, Specular Reflection, Scattered dmF=8nff
Transmission (BTDF). Scattered Reflection (BRDF), and Absorption. ?|5M'o|9
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For your property, I expect that Specular Transmission, Specular Reflection, vMz|'-rm$
and Absorption would all be 0, leaving only Scattered Transmission (BTDF). g{N}]_%Uh
Scattered Reflection (BRDF). BTDF and BRDF are controlled by 3 coefficients - ]9YA~n\
A, B, and g. For an initial estimate, I would suggest entering BTDF(g) = [Mu9"kF
BRDF(g) = 0, which defines a Lambertian dsitribution. rj=as>6B
rUK g<]&@
The challenge is to determine the proper ratio of Transmittance vs 9`f@"% h
Reflectance. You can enter a value for BRDF(A) and then use the Solve For 2K:A4)jZ
feature to solve for BTDF, and the editor will display the resulting g
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Integrated BTDF and Integrated BRDF values. You want these to sum to 1, and _^_3>}y5op
to have a ratio that matches the behavior of your surface. If the ratio of T ]
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vs R is dependent on the Incidence Angle, you can use the Add button in the Q/|.=:~FO
property to add Incidence ANgles to the table, and then define the BTDF and %IO*(5f
BRDF separately for each incidence angle.
