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The plastic material with the rough diffusing surface can be modeled in A[u B)wWsn
TracePro, but as two separate properties (select Define/EditPropertyData). .z^O y_S{
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MATERIAL PROPERTY g1@rY0O
A TracePro Material Property can be created, and the index of refraction of 9V >C %I
the material is entered here, as well as an absorption coefficient if it is RV%)~S@!R
known (this would be for absorption losses just from propogating through a RSC Q`.
given thickness of a clear polished sample of the material, unrelated to the FIx|4[&>S
diffusing surface finish. Entering zero for the absorption coefficient is F:8@ ]tA&
propobly a reasonable estimate for a transparent material. Xq}}T%jcd
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The Material Property is applied to the Object (Define/Apply Properties). &ju.5v|
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SURFACE PROPERTY ]d.e(yCuE
A TracePro Surface Property can specify 5 possible outcomes for light incident BDLJDyf B
on a surface - Specular Transmission, Specular Reflection, Scattered _}.WRFIJ@L
Transmission (BTDF). Scattered Reflection (BRDF), and Absorption. C9*[/| T
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For your property, I expect that Specular Transmission, Specular Reflection, 3Pvz5 7z{
and Absorption would all be 0, leaving only Scattered Transmission (BTDF). M5 ^qc
Scattered Reflection (BRDF). BTDF and BRDF are controlled by 3 coefficients - G+< id1
A, B, and g. For an initial estimate, I would suggest entering BTDF(g) = +'_ peT.8
BRDF(g) = 0, which defines a Lambertian dsitribution. *E+VcU
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The challenge is to determine the proper ratio of Transmittance vs U65oh8x
Reflectance. You can enter a value for BRDF(A) and then use the Solve For wQa,o l_p
feature to solve for BTDF, and the editor will display the resulting k]~$AaNq
Integrated BTDF and Integrated BRDF values. You want these to sum to 1, and \\3 ?ij:v
to have a ratio that matches the behavior of your surface. If the ratio of T D;[%*q*
vs R is dependent on the Incidence Angle, you can use the Add button in the ]} n|5
property to add Incidence ANgles to the table, and then define the BTDF and `uC^"R(m
BRDF separately for each incidence angle.
