站长说的很对,补充一下: EYUr.#:
Normal Vector s&lZxnIjc
The Normal Vector is a vector in 3D space that is used to orient the projection UJ)\E
^Hp
plane for the irradiance map. The plane is defined to be perpendicular to the 'MM#nQ\(
Normal Vector, and the irradiance incident on the selected surface is projected 4kA/W0 VG
onto this plane. When the map is displayed, the normal vector is pointing toward {
Lt\4h
you. }d)>pH
Up Vector cJm!3X
The Up Vector is a vector in 3D space that is used to orient the projection plane R$*{@U
for the irradiance map. The plane is defined so that the Up Vector is parallel to the fh
\<tnY
vertical side of the plane. The irradiance incident on the selected surface is T.HI
$(d
projected onto this plane. When the map is displayed, the up vector will point mB#`{|1[
toward the top of the screen.