站长说的很对,补充一下: Y5A~iGp8E
Normal Vector (h@yA8>n
The Normal Vector is a vector in 3D space that is used to orient the projection +VpE-X=T
plane for the irradiance map. The plane is defined to be perpendicular to the X^_+%U
Normal Vector, and the irradiance incident on the selected surface is projected I;11j
onto this plane. When the map is displayed, the normal vector is pointing toward
VjB`~
you. _F/lY\vm
Up Vector ZNH*[[Pf
The Up Vector is a vector in 3D space that is used to orient the projection plane 5 dNf$a0E
for the irradiance map. The plane is defined so that the Up Vector is parallel to the ]x(2}h^S
vertical side of the plane. The irradiance incident on the selected surface is m9<[bEO<$
projected onto this plane. When the map is displayed, the up vector will point LG@c)H74
toward the top of the screen.