站长说的很对,补充一下: y,tA~
Normal Vector sZ{Kl\1@
The Normal Vector is a vector in 3D space that is used to orient the projection "!i7U2M'
plane for the irradiance map. The plane is defined to be perpendicular to the B!K{y>|.
Normal Vector, and the irradiance incident on the selected surface is projected IJ3[6>/M0
onto this plane. When the map is displayed, the normal vector is pointing toward YES!?^}
you. a5{CkM&,(
Up Vector _-H uO/
The Up Vector is a vector in 3D space that is used to orient the projection plane !T@>Ld:
for the irradiance map. The plane is defined so that the Up Vector is parallel to the :
FF:{&d
vertical side of the plane. The irradiance incident on the selected surface is Z'6
o$Xv
projected onto this plane. When the map is displayed, the up vector will point !ge,]@/
toward the top of the screen.