站长说的很对,补充一下: UuWIT3W>%
Normal Vector XZb=;tYo
The Normal Vector is a vector in 3D space that is used to orient the projection )b #5rQ
plane for the irradiance map. The plane is defined to be perpendicular to the 0#9H;j<Op
Normal Vector, and the irradiance incident on the selected surface is projected "t&=~eOe3
onto this plane. When the map is displayed, the normal vector is pointing toward G;}WZy
you. !:!(=(4$P
Up Vector iR nj N
The Up Vector is a vector in 3D space that is used to orient the projection plane s|e.mZk/
for the irradiance map. The plane is defined so that the Up Vector is parallel to the q* p
vertical side of the plane. The irradiance incident on the selected surface is =^rt?F4
projected onto this plane. When the map is displayed, the up vector will point !xfDWbvHV
toward the top of the screen.