Solution: ?]5wX2G^|J
The plastic material with the rough diffusing surface can be modeled in [C7:Yg7
TracePro, but as two separate properties (select Define/EditPropertyData). x bn+9b
;&:UxmTf
MATERIAL PROPERTY }8x [
A TracePro Material Property can be created, and the index of refraction of I0OsaX'
the material is entered here, as well as an absorption coefficient if it is o"'VI4
known (this would be for absorption losses just from propogating through a sU+~#K$ b
given thickness of a clear polished sample of the material, unrelated to the *OsXjL`f
diffusing surface finish. Entering zero for the absorption coefficient is qZ8lU
propobly a reasonable estimate for a transparent material. |wK)(s
qn4Dm ^
The Material Property is applied to the Object (Define/Apply Properties). Az0Yt31 =
r2U2pAy#
SURFACE PROPERTY mP:mzmUw
A TracePro Surface Property can specify 5 possible outcomes for light incident 94K ;=5h
on a surface - Specular Transmission, Specular Reflection, Scattered dcXtT3,kpX
Transmission (BTDF). Scattered Reflection (BRDF), and Absorption. #2u-L ~n
s'/.ea V_
For your property, I expect that Specular Transmission, Specular Reflection, u&pLF%'EQ
and Absorption would all be 0, leaving only Scattered Transmission (BTDF). a?+) K
Scattered Reflection (BRDF). BTDF and BRDF are controlled by 3 coefficients - Txp~&a03
A, B, and g. For an initial estimate, I would suggest entering BTDF(g) = '| Ag,x[
BRDF(g) = 0, which defines a Lambertian dsitribution. 1X#`NUJ?2
'n> |jw)
The challenge is to determine the proper ratio of Transmittance vs G%'h'AV"
Reflectance. You can enter a value for BRDF(A) and then use the Solve For @&h<jM{D
feature to solve for BTDF, and the editor will display the resulting eeL%Yp3+
Integrated BTDF and Integrated BRDF values. You want these to sum to 1, and PT\5P&2o@
to have a ratio that matches the behavior of your surface. If the ratio of T 's&Vg09D,
vs R is dependent on the Incidence Angle, you can use the Add button in the ! '2'db
property to add Incidence ANgles to the table, and then define the BTDF and li; P,kg$
BRDF separately for each incidence angle.
