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The plastic material with the rough diffusing surface can be modeled in 7GP?;P
TracePro, but as two separate properties (select Define/EditPropertyData). fRa1m?%s
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MATERIAL PROPERTY <![T~<.
A TracePro Material Property can be created, and the index of refraction of r>)\"U#
the material is entered here, as well as an absorption coefficient if it is x9_ Lt4
known (this would be for absorption losses just from propogating through a v}_$9&|S
given thickness of a clear polished sample of the material, unrelated to the Xj-3C[ 8@
diffusing surface finish. Entering zero for the absorption coefficient is "Z{^i3 gN
propobly a reasonable estimate for a transparent material. {9l4 pT3
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The Material Property is applied to the Object (Define/Apply Properties). bm+ Mr
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SURFACE PROPERTY _?r+SRFn
A TracePro Surface Property can specify 5 possible outcomes for light incident }]s~L9_z['
on a surface - Specular Transmission, Specular Reflection, Scattered tRv#%>fj
Transmission (BTDF). Scattered Reflection (BRDF), and Absorption. cn\_;TYiJ
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For your property, I expect that Specular Transmission, Specular Reflection, e.jgV=dT-
and Absorption would all be 0, leaving only Scattered Transmission (BTDF). uyA9`~p=#
Scattered Reflection (BRDF). BTDF and BRDF are controlled by 3 coefficients - NFSPw` f
A, B, and g. For an initial estimate, I would suggest entering BTDF(g) = q(r2 \
BRDF(g) = 0, which defines a Lambertian dsitribution. F@I_sGCcb
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The challenge is to determine the proper ratio of Transmittance vs Yj"UD:p
Reflectance. You can enter a value for BRDF(A) and then use the Solve For { &qBr&kg
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 y1' /@A1
to have a ratio that matches the behavior of your surface. If the ratio of T S77Gc:[;8
vs R is dependent on the Incidence Angle, you can use the Add button in the ;I7Z*'5!
property to add Incidence ANgles to the table, and then define the BTDF and AHA*yC
BRDF separately for each incidence angle.
