站长说的很对，补充一下： 6&KvT2?tA`
Normal Vector Y24H`
s1u/
The Normal Vector is a vector in 3D space that is used to orient the projection d&ap u{
plane for the irradiance map. The plane is defined to be perpendicular to the h.WvPZ2U
Normal Vector, and the irradiance incident on the selected surface is projected /hksESiU
onto this plane. When the map is displayed, the normal vector is pointing toward GT3 ?)g{Z
you. &>$+O>c ,
Up Vector y)] L>o~
The Up Vector is a vector in 3D space that is used to orient the projection plane {j!+\neL
for the irradiance map. The plane is defined so that the Up Vector is parallel to the 3sF^6<E
vertical side of the plane. The irradiance incident on the selected surface is o b,%); m
projected onto this plane. When the map is displayed, the up vector will point ?X5Y8n]y\h
toward the top of the screen.
