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The plastic material with the rough diffusing surface can be modeled in ah x>q
TracePro, but as two separate properties (select Define/EditPropertyData). GjoIm?
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MATERIAL PROPERTY R_M?dEtE>
A TracePro Material Property can be created, and the index of refraction of SJD@&m%?[
the material is entered here, as well as an absorption coefficient if it is #/PA A
known (this would be for absorption losses just from propogating through a ~ wg:!VWA)
given thickness of a clear polished sample of the material, unrelated to the zvABU+{jD
diffusing surface finish. Entering zero for the absorption coefficient is V5+SWXZ
propobly a reasonable estimate for a transparent material. @SCI"H%[
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The Material Property is applied to the Object (Define/Apply Properties). "KcA
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SURFACE PROPERTY N0hE4t
A TracePro Surface Property can specify 5 possible outcomes for light incident f{SB1M
on a surface - Specular Transmission, Specular Reflection, Scattered YK|bXSA[
Transmission (BTDF). Scattered Reflection (BRDF), and Absorption. ^u 3V
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For your property, I expect that Specular Transmission, Specular Reflection, 8X bA'% o
and Absorption would all be 0, leaving only Scattered Transmission (BTDF). 74!oe u.>
Scattered Reflection (BRDF). BTDF and BRDF are controlled by 3 coefficients - LYlDc;<A
A, B, and g. For an initial estimate, I would suggest entering BTDF(g) = + QQS={
BRDF(g) = 0, which defines a Lambertian dsitribution. 2WUT/{:X
jzU .B u.
The challenge is to determine the proper ratio of Transmittance vs KWLbD#
Reflectance. You can enter a value for BRDF(A) and then use the Solve For 'SQG>F Uy
feature to solve for BTDF, and the editor will display the resulting h iN EJ_f
Integrated BTDF and Integrated BRDF values. You want these to sum to 1, and l5L.5 $N
to have a ratio that matches the behavior of your surface. If the ratio of T !i=nSqW
vs R is dependent on the Incidence Angle, you can use the Add button in the 9 \^|6k,
property to add Incidence ANgles to the table, and then define the BTDF and ~]ZpA-*@Ut
BRDF separately for each incidence angle.
