Solution: dv8>[#
The plastic material with the rough diffusing surface can be modeled in z=rT%lz6
TracePro, but as two separate properties (select Define/EditPropertyData). 'Jt]7;04p
tZ=E')!\
MATERIAL PROPERTY 96 q_ K84K
A TracePro Material Property can be created, and the index of refraction of R< ,`[* Z
the material is entered here, as well as an absorption coefficient if it is UDL!43 K
known (this would be for absorption losses just from propogating through a x(hE3S #+
given thickness of a clear polished sample of the material, unrelated to the e,F1Xi #d
diffusing surface finish. Entering zero for the absorption coefficient is Q1O}ly}JS
propobly a reasonable estimate for a transparent material. 6-yd]("
uw [<5
The Material Property is applied to the Object (Define/Apply Properties). F~%]6^$w
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SURFACE PROPERTY TH; R
A TracePro Surface Property can specify 5 possible outcomes for light incident me f<=5t
on a surface - Specular Transmission, Specular Reflection, Scattered C\/xl#e<@
Transmission (BTDF). Scattered Reflection (BRDF), and Absorption. ud xZ0
G;v8$) Zj
For your property, I expect that Specular Transmission, Specular Reflection, %+8F'&X
and Absorption would all be 0, leaving only Scattered Transmission (BTDF). WM| dKF
Scattered Reflection (BRDF). BTDF and BRDF are controlled by 3 coefficients - tk!t
Y8j
A, B, and g. For an initial estimate, I would suggest entering BTDF(g) = xC*6vH]?
BRDF(g) = 0, which defines a Lambertian dsitribution. w[9|cg CY
As 3.Q(#Z
The challenge is to determine the proper ratio of Transmittance vs mQCeo}7N5
Reflectance. You can enter a value for BRDF(A) and then use the Solve For 56+s~hG
feature to solve for BTDF, and the editor will display the resulting lsNrAA%m
Integrated BTDF and Integrated BRDF values. You want these to sum to 1, and (g[h
8
c
to have a ratio that matches the behavior of your surface. If the ratio of T B^j
vs R is dependent on the Incidence Angle, you can use the Add button in the 0~ZFv Wv
property to add Incidence ANgles to the table, and then define the BTDF and b iSz?DJ>
BRDF separately for each incidence angle.
