看一下幫助,裡面有 xlu4
INTERFACE r [ t m m'] ? /*,_\ ;
COAT k coat coat' O^row1D_
-k S7Ty}?E@
+k =3w;<1 ?'
The signs in front of k can be used to instruct ASAP to either propagate only a reflected ray (-k: t=0) at that object or to propagate only a transmitted ray (+k: r=0) at that object. ;%^=V#
+ 指只有折射沒有反射光, LlO8]b!P-^
- 指只有反射沒有折射。