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The plastic material with the rough diffusing surface can be modeled in -q)|I|y*7
TracePro, but as two separate properties (select Define/EditPropertyData). mGwJ>'+d
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MATERIAL PROPERTY _;x` 6LM
A TracePro Material Property can be created, and the index of refraction of 7!o#pt7
the material is entered here, as well as an absorption coefficient if it is ~yngH0S$[b
known (this would be for absorption losses just from propogating through a ;eFV}DWW
given thickness of a clear polished sample of the material, unrelated to the wko9tdC=U
diffusing surface finish. Entering zero for the absorption coefficient is ^755 LW
propobly a reasonable estimate for a transparent material. ELG{xN=o
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The Material Property is applied to the Object (Define/Apply Properties). &f A1kG%
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SURFACE PROPERTY Rc@lGq9
A TracePro Surface Property can specify 5 possible outcomes for light incident \ z*<^ONq
on a surface - Specular Transmission, Specular Reflection, Scattered /a$Zzs&xs
Transmission (BTDF). Scattered Reflection (BRDF), and Absorption. .ezko\nU
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For your property, I expect that Specular Transmission, Specular Reflection, KB \ri&bF
and Absorption would all be 0, leaving only Scattered Transmission (BTDF). fP;I{AiN~
Scattered Reflection (BRDF). BTDF and BRDF are controlled by 3 coefficients - Q^Vch(`&P
A, B, and g. For an initial estimate, I would suggest entering BTDF(g) = =L"I[
BRDF(g) = 0, which defines a Lambertian dsitribution. FAGi`X<L
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The challenge is to determine the proper ratio of Transmittance vs H11@ DQ6
Reflectance. You can enter a value for BRDF(A) and then use the Solve For frQ=BV5%6
feature to solve for BTDF, and the editor will display the resulting q` |E9
Integrated BTDF and Integrated BRDF values. You want these to sum to 1, and D+BflI~9mP
to have a ratio that matches the behavior of your surface. If the ratio of T ]]u_Mdk
vs R is dependent on the Incidence Angle, you can use the Add button in the vl`St$$|
property to add Incidence ANgles to the table, and then define the BTDF and 'w;J) _Yc2
BRDF separately for each incidence angle.
