Solution: S/hQZHZHg,
The plastic material with the rough diffusing surface can be modeled in & bm
1 Fz
TracePro, but as two separate properties (select Define/EditPropertyData). ?/E~/;+ 7=
tyDU
@M
MATERIAL PROPERTY IJp-BTO{V
A TracePro Material Property can be created, and the index of refraction of #4NaL
the material is entered here, as well as an absorption coefficient if it is 7vKK%H_P
known (this would be for absorption losses just from propogating through a 6dr% ;Wp
given thickness of a clear polished sample of the material, unrelated to the fCn^=8KOZ
diffusing surface finish. Entering zero for the absorption coefficient is ; W
)Y
OT
propobly a reasonable estimate for a transparent material. <]t%8GB2V
e;q!6%
The Material Property is applied to the Object (Define/Apply Properties). 2eS~/Pq5=i
`:fZ)$sY
SURFACE PROPERTY Lz Kj=5'Y
A TracePro Surface Property can specify 5 possible outcomes for light incident ./Zk`-OBT
on a surface - Specular Transmission, Specular Reflection, Scattered LKB$,pR~1l
Transmission (BTDF). Scattered Reflection (BRDF), and Absorption. nsC3
U [-o> W#
For your property, I expect that Specular Transmission, Specular Reflection,
=%K;X\NB
and Absorption would all be 0, leaving only Scattered Transmission (BTDF). z6\UGSL
Scattered Reflection (BRDF). BTDF and BRDF are controlled by 3 coefficients - _Kf% \xg
A, B, and g. For an initial estimate, I would suggest entering BTDF(g) = Ms#M+[ a
BRDF(g) = 0, which defines a Lambertian dsitribution. N7zf t
yjX9oxhtL
The challenge is to determine the proper ratio of Transmittance vs ZgcMv,=
Reflectance. You can enter a value for BRDF(A) and then use the Solve For h
0Q5-EA
feature to solve for BTDF, and the editor will display the resulting '3tCH)s
Integrated BTDF and Integrated BRDF values. You want these to sum to 1, and UYJZ YP%r
to have a ratio that matches the behavior of your surface. If the ratio of T 1<@W6@]
vs R is dependent on the Incidence Angle, you can use the Add button in the ;?i W%:_,
property to add Incidence ANgles to the table, and then define the BTDF and oxA<VWUNT
BRDF separately for each incidence angle.
