站長說的很對，補充一下： `\ef0
Normal Vector " _:iK]
The Normal Vector is a vector in 3D space that is used to orient the projection c8-69hb?
plane for the irradiance map. The plane is defined to be perpendicular to the r v,NQZ
Normal Vector, and the irradiance incident on the selected surface is projected { \svV
0)~
onto this plane. When the map is displayed, the normal vector is pointing toward K$<`4#i
you. 4+5OR&kxZ
Up Vector \[[TlB>
The Up Vector is a vector in 3D space that is used to orient the projection plane sb}K%-
for the irradiance map. The plane is defined so that the Up Vector is parallel to the *>aZc::
vertical side of the plane. The irradiance incident on the selected surface is T2 :oWjC3$
projected onto this plane. When the map is displayed, the up vector will point ~m?74^ i
toward the top of the screen.
