站长说的很对，补充一下： wm)#[x #
Normal Vector W6"v)Jc>_
The Normal Vector is a vector in 3D space that is used to orient the projection bty/
plane for the irradiance map. The plane is defined to be perpendicular to the } w
5 l
Normal Vector, and the irradiance incident on the selected surface is projected IG|X!l
onto this plane. When the map is displayed, the normal vector is pointing toward x9;gT&@H
you. 7Garnd b
Up Vector BO~PT,QrF
The Up Vector is a vector in 3D space that is used to orient the projection plane MxGu> r
for the irradiance map. The plane is defined so that the Up Vector is parallel to the L5#P[cHzz
vertical side of the plane. The irradiance incident on the selected surface is Q(<)KZIK
projected onto this plane. When the map is displayed, the up vector will point s<oNE)xe
toward the top of the screen.
