站长说的很对，补充一下： meD (ja
Normal Vector L=FvLii.
The Normal Vector is a vector in 3D space that is used to orient the projection Y-{BY5E.
plane for the irradiance map. The plane is defined to be perpendicular to the "kg$s5o
Normal Vector, and the irradiance incident on the selected surface is projected A :J{
onto this plane. When the map is displayed, the normal vector is pointing toward Y- -8v#t
you. bD-Em#>
Up Vector ?0%TE\I8
The Up Vector is a vector in 3D space that is used to orient the projection plane 6+z]MT
for the irradiance map. The plane is defined so that the Up Vector is parallel to the GK%ovK
vertical side of the plane. The irradiance incident on the selected surface is gQDK?aQX
projected onto this plane. When the map is displayed, the up vector will point \ \}/2#1=c
toward the top of the screen.
