Solution: o,q47W=7$
The plastic material with the rough diffusing surface can be modeled in sX
c|++
TracePro, but as two separate properties (select Define/EditPropertyData). `zP{E T_Y
2R`dyg
MATERIAL PROPERTY nYb{?{_ca8
A TracePro Material Property can be created, and the index of refraction of oro^'# ki
the material is entered here, as well as an absorption coefficient if it is 1w$X;q"
known (this would be for absorption losses just from propogating through a Vb++K0CK
given thickness of a clear polished sample of the material, unrelated to the \:5 M0
diffusing surface finish. Entering zero for the absorption coefficient is &_o.:SL|
propobly a reasonable estimate for a transparent material. V"u .u
AM:lU
The Material Property is applied to the Object (Define/Apply Properties). XIRvIwO
r YfN
SURFACE PROPERTY sKniqWi
A TracePro Surface Property can specify 5 possible outcomes for light incident $gPR3*0
on a surface - Specular Transmission, Specular Reflection, Scattered &57s //PrX
Transmission (BTDF). Scattered Reflection (BRDF), and Absorption. 5)=YTUCk
QT)5-Jy
For your property, I expect that Specular Transmission, Specular Reflection, TD^w|U.
and Absorption would all be 0, leaving only Scattered Transmission (BTDF). zy\R>4i'#Q
Scattered Reflection (BRDF). BTDF and BRDF are controlled by 3 coefficients - ) 2&y;{]
A, B, and g. For an initial estimate, I would suggest entering BTDF(g) = vD9 1t/_+
BRDF(g) = 0, which defines a Lambertian dsitribution. m[$pj~<\
&Ndq ^!e
The challenge is to determine the proper ratio of Transmittance vs 9~|hG o
Reflectance. You can enter a value for BRDF(A) and then use the Solve For oeA}b-Ct0
feature to solve for BTDF, and the editor will display the resulting ;vp[J&=
Integrated BTDF and Integrated BRDF values. You want these to sum to 1, and 'FC#O%l
to have a ratio that matches the behavior of your surface. If the ratio of T Scz/2vNi`
vs R is dependent on the Incidence Angle, you can use the Add button in the ]S0 sjN
property to add Incidence ANgles to the table, and then define the BTDF and b Sm*/Q
BRDF separately for each incidence angle.
