站长说的很对,补充一下: RHB>svT^K>
Normal Vector .g4bV5ma3
The Normal Vector is a vector in 3D space that is used to orient the projection !_V*VD
plane for the irradiance map. The plane is defined to be perpendicular to the KN+*_L-
Normal Vector, and the irradiance incident on the selected surface is projected {d7KJmN
onto this plane. When the map is displayed, the normal vector is pointing toward ulVHsWg
you. *(r85lEou)
Up Vector B VPf8!-
The Up Vector is a vector in 3D space that is used to orient the projection plane TWxMexiW
for the irradiance map. The plane is defined so that the Up Vector is parallel to the 9`c :sop
vertical side of the plane. The irradiance incident on the selected surface is <cWo]T`X!
projected onto this plane. When the map is displayed, the up vector will point ^s24f?3
toward the top of the screen.