ASAP问题

这是一个简单方形的管子,但是运行之后怎么会出现光线呢?(见最后一图,管子边框为光线)
我明明没有定义光线的.请大家帮我指出错误. 附件为图形
SYSTEM NEW
RESET
UNITS MM
MEDIA
1.52 'PLASTIC'
FRESNEL AVE      !! Calculate Fresnel reflections,
                                 !! averaging the flux of the two
                                  !! polarization states.
HLONG=30/2        
HWIDE=0.5/2        
HTHICK=0.5/2     
GAP=0.001         
                 
SURFACE
PLANE X (HTHICK) RECTANGLE (HWIDE) (HLONG)
OBJECT '1'
INTERFACE COATING BARE AIR PLASTIC
SURFACE
PLANE X (-HTHICK) RECTANGLE (HWIDE) (HLONG)
OBJECT '2'
INTERFACE COATING BARE AIR PLASTIC
SURFACE
PLANE Z (-HLONG) RECTANGLE (HTHICK) (HWIDE)
OBJECT '3'
INTERFACE COATING BARE AIR PLASTIC
SURFACE
PLANE Z (HLONG) RECTANGLE (HTHICK) (HWIDE)
OBJECT '4'
INTERFACE COATING BARE AIR PLASTIC
SURFACE
PLANE Y (-HWIDE) RECTANGLE (HLONG) (HTHICK)
OBJECT '5'
INTERFACE COATING BARE AIR PLASTIC
SURFACE
PLANE Y (HWIDE) RECTANGLE (HLONG) (HTHICK)
OBJECT '6'
INTERFACE COATING BARE AIR PLASTIC
                                                
                                                
RETURN  
PLOT FACET 5 5
WINDOW X Y
OBLIQUE
PLOT LOCALS OVERLAY ' the light pipe'

程序

晕了,哪来的光线?

[ 本帖最后由 guoxuemiao 于 2008-2-28 11:15 编辑 ]

PLOT LOCALS OVERLAY ' the light pipe' ------- 是POLT LOCALS 生成一个框图 . he he

PLOT LOCALS OVERLAY ' the light pipe' ------- 是POLT LOCALS 生成一个框图,
还是不明白.

如果不执行PLOT LOCALS OVERLAY ' the light pipe'这个语句
那么3D里只有6个面
执行PLOT LOCALS OVERLAY ' the light pipe'这个语句后
在3D里除 6个面外增加了一项RAYS,SPOTS,LINE PLOTS,et cetera
但是这项不是光源，只是plot locals命令产生的线框