Solution: r'&9'rir2
The plastic material with the rough diffusing surface can be modeled in j\dkv_L
TracePro, but as two separate properties (select Define/EditPropertyData). 7@EYF
$'9r=#EH
MATERIAL PROPERTY OM!ES%c,
A TracePro Material Property can be created, and the index of refraction of W %R h2l
the material is entered here, as well as an absorption coefficient if it is 4C01=,6ye
known (this would be for absorption losses just from propogating through a -#gb {vj
given thickness of a clear polished sample of the material, unrelated to the 8ZG'?A+{
diffusing surface finish. Entering zero for the absorption coefficient is o,\%c" mC
propobly a reasonable estimate for a transparent material. O|y-nAZgU
P60 3P
The Material Property is applied to the Object (Define/Apply Properties). CM5A-R90
x0lX6
|D
SURFACE PROPERTY h *%T2
A TracePro Surface Property can specify 5 possible outcomes for light incident ,C&h~uRi#f
on a surface - Specular Transmission, Specular Reflection, Scattered Q^MB%L;D
Transmission (BTDF). Scattered Reflection (BRDF), and Absorption. :R_{tQ-WG
n#J$=@
For your property, I expect that Specular Transmission, Specular Reflection, =53LapTPJ
and Absorption would all be 0, leaving only Scattered Transmission (BTDF). i+&= "Z@
Scattered Reflection (BRDF). BTDF and BRDF are controlled by 3 coefficients - 'R] Z 9h
A, B, and g. For an initial estimate, I would suggest entering BTDF(g) = R X2=
iO"
BRDF(g) = 0, which defines a Lambertian dsitribution. t_]UseP$RF
g=U?{<8.m
The challenge is to determine the proper ratio of Transmittance vs 7vj[ AOq3l
Reflectance. You can enter a value for BRDF(A) and then use the Solve For ljt1:@SN(
feature to solve for BTDF, and the editor will display the resulting mH{cGu?
Integrated BTDF and Integrated BRDF values. You want these to sum to 1, and (
?/0$DB
to have a ratio that matches the behavior of your surface. If the ratio of T huKz["]z[
vs R is dependent on the Incidence Angle, you can use the Add button in the Plq [Ml9
property to add Incidence ANgles to the table, and then define the BTDF and =r-Wy.a@
BRDF separately for each incidence angle.
