Solution: 7 R1;'/;
The plastic material with the rough diffusing surface can be modeled in Q7PqN1jTE
TracePro, but as two separate properties (select Define/EditPropertyData). 0-dh Gh?.
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MATERIAL PROPERTY AuZ?~I1
A TracePro Material Property can be created, and the index of refraction of ,nO:Pxn|
the material is entered here, as well as an absorption coefficient if it is wzAp`Zs2Dm
known (this would be for absorption losses just from propogating through a ]1]
given thickness of a clear polished sample of the material, unrelated to the E.Hw|y0_(|
diffusing surface finish. Entering zero for the absorption coefficient is HaeF`gI^Ee
propobly a reasonable estimate for a transparent material. 3mWd?!+m=
Q"]C" ?
The Material Property is applied to the Object (Define/Apply Properties). @:DS/#!
|L{<=NNs:D
SURFACE PROPERTY =dbLA ,z9
A TracePro Surface Property can specify 5 possible outcomes for light incident KZV$rJ%G
on a surface - Specular Transmission, Specular Reflection, Scattered ?5m[Qc (<
Transmission (BTDF). Scattered Reflection (BRDF), and Absorption. e=nEx Y
7M: 0%n$
For your property, I expect that Specular Transmission, Specular Reflection, 'Mjbvh4
and Absorption would all be 0, leaving only Scattered Transmission (BTDF). , cm;A'4]
Scattered Reflection (BRDF). BTDF and BRDF are controlled by 3 coefficients - Z iDmx-X
A, B, and g. For an initial estimate, I would suggest entering BTDF(g) = g<~[k?~J
BRDF(g) = 0, which defines a Lambertian dsitribution. h+$1+Es
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The challenge is to determine the proper ratio of Transmittance vs 8<u_ wt@
Reflectance. You can enter a value for BRDF(A) and then use the Solve For ;2RCgX!'%
feature to solve for BTDF, and the editor will display the resulting 5v8&C2Jy@
Integrated BTDF and Integrated BRDF values. You want these to sum to 1, and ]zVe% Wa
to have a ratio that matches the behavior of your surface. If the ratio of T 8}p 5 MG
vs R is dependent on the Incidence Angle, you can use the Add button in the k}-%NkQ
9O
property to add Incidence ANgles to the table, and then define the BTDF and ,2?"W8,
BRDF separately for each incidence angle.
