斑主用的是哪個版本的ＴＰ��？４..０以前版本的manual有沒mentioned？

Solution: T+Du/ERL  
The plastic material with the rough diffusing surface can be modeled in FzW7MW>\x  
TracePro, but as two separate properties (select Define/EditPropertyData). MT}9T  
PWmFY'=  
MATERIAL PROPERTY @2Z{en?  
A TracePro Material Property can be created, and the index of refraction of 8,=,'gFO  
the material is entered here, as well as an absorption coefficient if it is -PoW56  
known (this would be for absorption losses just from propogating through a ~xkcQ{  
given thickness of a clear polished sample of the material, unrelated to the CKy' 8I9  
diffusing surface finish.  Entering zero for the absorption coefficient is HZ )z^K?1  
propobly a reasonable estimate for a transparent material. RQ!kVM@  
sYYNT*  
The Material Property is applied to the Object (Define/Apply Properties). <Y9e n!3\  
2w+w'Ag_R  
SURFACE PROPERTY xrf z-"n4  
A TracePro Surface Property can specify 5 possible outcomes for light incident &r doMc;  
on a surface - Specular Transmission, Specular Reflection, Scattered 5{L~e>oS9  
Transmission (BTDF). Scattered Reflection (BRDF), and Absorption. KZ>cfv-&a  
>-0Rq[)  
For your property, I expect that Specular Transmission, Specular Reflection, 4*P#3 B'@V  
and Absorption would all be 0, leaving only Scattered Transmission (BTDF). J>TNyVaoQ  
Scattered Reflection (BRDF).  BTDF and BRDF are controlled by 3 coefficients - +9<"Y6  
A, B, and g.  For an initial estimate, I would suggest entering BTDF(g) = +d>?aqI\A  
BRDF(g) = 0, which defines a Lambertian dsitribution. e?,n>