Solution: I*^3 Z
The plastic material with the rough diffusing surface can be modeled in +k4 SN
TracePro, but as two separate properties (select Define/EditPropertyData). i%)Nn^a;T
v/yt C/WH"
MATERIAL PROPERTY =K2mR}n\;
A TracePro Material Property can be created, and the index of refraction of cCH2=v4hU
the material is entered here, as well as an absorption coefficient if it is &% \`Lwh
known (this would be for absorption losses just from propogating through a '
Z}/3 d p
given thickness of a clear polished sample of the material, unrelated to the s$ 2@ |;
diffusing surface finish. Entering zero for the absorption coefficient is T=QV =21qn
propobly a reasonable estimate for a transparent material. :3x |U,wC
,,>b=r_r&
The Material Property is applied to the Object (Define/Apply Properties). " '/$ZpY
^#4?v^QNh
SURFACE PROPERTY -v(.]`Wo&;
A TracePro Surface Property can specify 5 possible outcomes for light incident l;dZJ_Ut$
on a surface - Specular Transmission, Specular Reflection, Scattered NN9` jP2
Transmission (BTDF). Scattered Reflection (BRDF), and Absorption. R2af >R
WurpHOJt+
For your property, I expect that Specular Transmission, Specular Reflection, @*gm\sU4
and Absorption would all be 0, leaving only Scattered Transmission (BTDF). a9GLFA8Vq
Scattered Reflection (BRDF). BTDF and BRDF are controlled by 3 coefficients - Z) zWfv}
A, B, and g. For an initial estimate, I would suggest entering BTDF(g) = %?3\gFvBo
BRDF(g) = 0, which defines a Lambertian dsitribution. N}3$1=@Y
|E)Es!dr
The challenge is to determine the proper ratio of Transmittance vs t zhkdG
Reflectance. You can enter a value for BRDF(A) and then use the Solve For ^c{,QS{
feature to solve for BTDF, and the editor will display the resulting xED`8PCfu
Integrated BTDF and Integrated BRDF values. You want these to sum to 1, and zW_V)U Ne
to have a ratio that matches the behavior of your surface. If the ratio of T {g>k -.
vs R is dependent on the Incidence Angle, you can use the Add button in the {<HL}m@kQ
property to add Incidence ANgles to the table, and then define the BTDF and ,HxsU,xiG
BRDF separately for each incidence angle.
