站长说的很对,补充一下: >`!Lh`n7_
Normal Vector u'Ua ++a\
The Normal Vector is a vector in 3D space that is used to orient the projection 8 ,<F102(
plane for the irradiance map. The plane is defined to be perpendicular to the BD (
Normal Vector, and the irradiance incident on the selected surface is projected C@Fk
onto this plane. When the map is displayed, the normal vector is pointing toward Y)]x1I
you. ley:=(
Up Vector [qGj*`@C
The Up Vector is a vector in 3D space that is used to orient the projection plane v08Xe*gNU
for the irradiance map. The plane is defined so that the Up Vector is parallel to the )=c/{
vertical side of the plane. The irradiance incident on the selected surface is f)/5%W7n}
projected onto this plane. When the map is displayed, the up vector will point b63 tjqk
toward the top of the screen.