Solution: U%mkhWn
The plastic material with the rough diffusing surface can be modeled in @- )<|orU4
TracePro, but as two separate properties (select Define/EditPropertyData). 3q~":bpAp
Q3<bC6$r
MATERIAL PROPERTY p)?qJ2c|
A TracePro Material Property can be created, and the index of refraction of ?z \q Mu
the material is entered here, as well as an absorption coefficient if it is ikEWY_1Y
known (this would be for absorption losses just from propogating through a ]`#xR *a
given thickness of a clear polished sample of the material, unrelated to the S5: "_U
diffusing surface finish. Entering zero for the absorption coefficient is m.\ >95!
propobly a reasonable estimate for a transparent material. `c qH}2s#
9 _M H
The Material Property is applied to the Object (Define/Apply Properties). c,v^A+s Zu
=yk Rki
SURFACE PROPERTY #~bU}[{
A TracePro Surface Property can specify 5 possible outcomes for light incident !$:0E
y(S
on a surface - Specular Transmission, Specular Reflection, Scattered q7 %=`l
Transmission (BTDF). Scattered Reflection (BRDF), and Absorption. N.fQ7z=Z(M
b
xk'a,!S
For your property, I expect that Specular Transmission, Specular Reflection, ]y1$F
Ir+
and Absorption would all be 0, leaving only Scattered Transmission (BTDF). s)=!2A Y
Scattered Reflection (BRDF). BTDF and BRDF are controlled by 3 coefficients - l>3M|js@/
A, B, and g. For an initial estimate, I would suggest entering BTDF(g) = 2.fyP"P
L
BRDF(g) = 0, which defines a Lambertian dsitribution. mhHA!:Y
Q%,o8E2~
The challenge is to determine the proper ratio of Transmittance vs 1S*8v 7
Reflectance. You can enter a value for BRDF(A) and then use the Solve For dCf'\ @<<
feature to solve for BTDF, and the editor will display the resulting
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Integrated BTDF and Integrated BRDF values. You want these to sum to 1, and H{ n>KZ]\
to have a ratio that matches the behavior of your surface. If the ratio of T Mr5('9%
vs R is dependent on the Incidence Angle, you can use the Add button in the _Ewy^;S%L
property to add Incidence ANgles to the table, and then define the BTDF and ! # ,-
BRDF separately for each incidence angle.
