Solution: X+UJzR90
The plastic material with the rough diffusing surface can be modeled in Xs: 3'ua
TracePro, but as two separate properties (select Define/EditPropertyData). 8Nu=^[qwQM
9mA{K
MATERIAL PROPERTY q$I:`&
A TracePro Material Property can be created, and the index of refraction of 3k#~yaoI
the material is entered here, as well as an absorption coefficient if it is nRyU]=-X
known (this would be for absorption losses just from propogating through a =UUU$hq2
given thickness of a clear polished sample of the material, unrelated to the Zm6{n '
diffusing surface finish. Entering zero for the absorption coefficient is sMu]
/'7
propobly a reasonable estimate for a transparent material. .o) `m9/
I(S`j[U
The Material Property is applied to the Object (Define/Apply Properties). a ~'a
wgCa58H76
SURFACE PROPERTY hjZKUM G(k
A TracePro Surface Property can specify 5 possible outcomes for light incident R(q~ -3~
on a surface - Specular Transmission, Specular Reflection, Scattered d3=KTTi\
Transmission (BTDF). Scattered Reflection (BRDF), and Absorption. [Xb@Wh:yG
g+J-Zg6
For your property, I expect that Specular Transmission, Specular Reflection, 5[c^TJ3
and Absorption would all be 0, leaving only Scattered Transmission (BTDF). H\TI[JPAl
Scattered Reflection (BRDF). BTDF and BRDF are controlled by 3 coefficients - PLK3v4kVM!
A, B, and g. For an initial estimate, I would suggest entering BTDF(g) = j~!X;PV3
BRDF(g) = 0, which defines a Lambertian dsitribution. &mb{.=
293M\5:
The challenge is to determine the proper ratio of Transmittance vs oYukLr
Reflectance. You can enter a value for BRDF(A) and then use the Solve For : |>Gc39`t
feature to solve for BTDF, and the editor will display the resulting C=eF.FB;'
Integrated BTDF and Integrated BRDF values. You want these to sum to 1, and r-:Uz\gM
to have a ratio that matches the behavior of your surface. If the ratio of T vM5k _D
vs R is dependent on the Incidence Angle, you can use the Add button in the zux{S; :?
property to add Incidence ANgles to the table, and then define the BTDF and {{QELfH2
BRDF separately for each incidence angle.
