站长说的很对,补充一下: 6O'6,%#
Normal Vector ~[4zm$R^
The Normal Vector is a vector in 3D space that is used to orient the projection ]$?\,`
plane for the irradiance map. The plane is defined to be perpendicular to the "\1QJ
Normal Vector, and the irradiance incident on the selected surface is projected Y!lc/[8
onto this plane. When the map is displayed, the normal vector is pointing toward uM('R;<^
you. dSIZsapH
Up Vector E>O1dPZcM
The Up Vector is a vector in 3D space that is used to orient the projection plane -87]$ ax
for the irradiance map. The plane is defined so that the Up Vector is parallel to the y`.m'n7>P
vertical side of the plane. The irradiance incident on the selected surface is $+@xwuY'+
projected onto this plane. When the map is displayed, the up vector will point dX5|A_Ex
toward the top of the screen.