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The plastic material with the rough diffusing surface can be modeled in UDr 1t n
TracePro, but as two separate properties (select Define/EditPropertyData). B1_9l3RM
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MATERIAL PROPERTY UxNn5(:sM@
A TracePro Material Property can be created, and the index of refraction of "b`#RohCi
the material is entered here, as well as an absorption coefficient if it is VQpt1cK*
known (this would be for absorption losses just from propogating through a a Int[D(
given thickness of a clear polished sample of the material, unrelated to the 9< ?w9 D.1
diffusing surface finish. Entering zero for the absorption coefficient is tcj "rV{G
propobly a reasonable estimate for a transparent material. Pg T3E
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The Material Property is applied to the Object (Define/Apply Properties). +h"i6`g
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SURFACE PROPERTY h@R n)D
A TracePro Surface Property can specify 5 possible outcomes for light incident ]7_>l>
on a surface - Specular Transmission, Specular Reflection, Scattered }PK4
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Transmission (BTDF). Scattered Reflection (BRDF), and Absorption. S|tA%2z
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For your property, I expect that Specular Transmission, Specular Reflection, fQib?g/G
and Absorption would all be 0, leaving only Scattered Transmission (BTDF). Xw9]WJc
Scattered Reflection (BRDF). BTDF and BRDF are controlled by 3 coefficients - 8J'5%$3u
A, B, and g. For an initial estimate, I would suggest entering BTDF(g) = ra*|HcLD
BRDF(g) = 0, which defines a Lambertian dsitribution. ~$6` e:n
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The challenge is to determine the proper ratio of Transmittance vs A[m?^vk q
Reflectance. You can enter a value for BRDF(A) and then use the Solve For sC\?{B0 r
feature to solve for BTDF, and the editor will display the resulting C '[4jz0xF
Integrated BTDF and Integrated BRDF values. You want these to sum to 1, and vxPE=!|
to have a ratio that matches the behavior of your surface. If the ratio of T (9]1p;
vs R is dependent on the Incidence Angle, you can use the Add button in the _DSDY$ Ec
property to add Incidence ANgles to the table, and then define the BTDF and LAc60^t1
BRDF separately for each incidence angle.
