Solution: T^DJ/uhd
The plastic material with the rough diffusing surface can be modeled in <} Hs@`jS
TracePro, but as two separate properties (select Define/EditPropertyData). 0}3Xry,{
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MATERIAL PROPERTY '/'dg5bfV
A TracePro Material Property can be created, and the index of refraction of $.F.xYS9IJ
the material is entered here, as well as an absorption coefficient if it is DLH|y%"
known (this would be for absorption losses just from propogating through a P^57a?[`
given thickness of a clear polished sample of the material, unrelated to the d` X1cG
diffusing surface finish. Entering zero for the absorption coefficient is mv{bX|.
propobly a reasonable estimate for a transparent material. w(oi6kg
Yv/T6z@
The Material Property is applied to the Object (Define/Apply Properties). ".7\>8A#a
+GvP JI
SURFACE PROPERTY 045_0+r"@
A TracePro Surface Property can specify 5 possible outcomes for light incident phi9/tO\u
on a surface - Specular Transmission, Specular Reflection, Scattered e X{#F gFc
Transmission (BTDF). Scattered Reflection (BRDF), and Absorption. eX AJ%^iD
yA]OX" T?*
For your property, I expect that Specular Transmission, Specular Reflection, n 09P!],Xa
and Absorption would all be 0, leaving only Scattered Transmission (BTDF). aw l3|k/
Scattered Reflection (BRDF). BTDF and BRDF are controlled by 3 coefficients - A4daIhP
(
A, B, and g. For an initial estimate, I would suggest entering BTDF(g) = [?55vYt
BRDF(g) = 0, which defines a Lambertian dsitribution. ;R([w4[~
P$zhMnAAN
The challenge is to determine the proper ratio of Transmittance vs X#k:J
Reflectance. You can enter a value for BRDF(A) and then use the Solve For WR p0.
feature to solve for BTDF, and the editor will display the resulting )?{jD
Integrated BTDF and Integrated BRDF values. You want these to sum to 1, and d]K$0HY
to have a ratio that matches the behavior of your surface. If the ratio of T |@BX*r
vs R is dependent on the Incidence Angle, you can use the Add button in the -<l2 $&KS
property to add Incidence ANgles to the table, and then define the BTDF and uQYenCNXS
BRDF separately for each incidence angle.
