檢視 NegF 的原始碼

=='''Format'''==
 NegF // integer

<font size=3>
Flag for reversing the direction of emission light ray. If the flag is True, then the ray is emitted toward the direction <math>-\hat n</math> where <math>\hat n</math> is the normal vector of the surface.
</font>

=='''Example'''==
 #NegF
 SurfEmit
 Shell 1 
 1

The direction is reversed.