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The plastic material with the rough diffusing surface can be modeled in !zZ3F|+HB
TracePro, but as two separate properties (select Define/EditPropertyData). ]5',`~jkF
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MATERIAL PROPERTY ' 5xvR G
A TracePro Material Property can be created, and the index of refraction of dQQ!QbI(.
the material is entered here, as well as an absorption coefficient if it is t8ZzBD!dP
known (this would be for absorption losses just from propogating through a o FS2*u
given thickness of a clear polished sample of the material, unrelated to the 2/>u8j
diffusing surface finish. Entering zero for the absorption coefficient is *w`_(X f
propobly a reasonable estimate for a transparent material. Z'!i"Jzq|{
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The Material Property is applied to the Object (Define/Apply Properties). 'D:R]@eK]
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SURFACE PROPERTY [aF"5G
A TracePro Surface Property can specify 5 possible outcomes for light incident =fcM2O #$
on a surface - Specular Transmission, Specular Reflection, Scattered X8\UTHT& 0
Transmission (BTDF). Scattered Reflection (BRDF), and Absorption. + usB$=kJ
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For your property, I expect that Specular Transmission, Specular Reflection, 5rH?FQE
and Absorption would all be 0, leaving only Scattered Transmission (BTDF). ]RxJ^'a63
Scattered Reflection (BRDF). BTDF and BRDF are controlled by 3 coefficients - ey@{Ng#
A, B, and g. For an initial estimate, I would suggest entering BTDF(g) = ]R*h3U@5#K
BRDF(g) = 0, which defines a Lambertian dsitribution. q x1+ '
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The challenge is to determine the proper ratio of Transmittance vs vI20G89E
Reflectance. You can enter a value for BRDF(A) and then use the Solve For r7jh)Q;BbR
feature to solve for BTDF, and the editor will display the resulting {` ByZB
Integrated BTDF and Integrated BRDF values. You want these to sum to 1, and =eyPo(B
to have a ratio that matches the behavior of your surface. If the ratio of T M3VTzwuf^S
vs R is dependent on the Incidence Angle, you can use the Add button in the <%N*IE"q
property to add Incidence ANgles to the table, and then define the BTDF and @g nLY
BRDF separately for each incidence angle.
