站长说的很对,补充一下: OD-CU8X9
Normal Vector *v)JX _
The Normal Vector is a vector in 3D space that is used to orient the projection iJv4%|9
plane for the irradiance map. The plane is defined to be perpendicular to the y44FejH(v
Normal Vector, and the irradiance incident on the selected surface is projected ywXerz7dUk
onto this plane. When the map is displayed, the normal vector is pointing toward S5*wUd*p#
you. :~3sW< PR
Up Vector <"{Lv)4
The Up Vector is a vector in 3D space that is used to orient the projection plane L MC-1
for the irradiance map. The plane is defined so that the Up Vector is parallel to the pg1o@^OuL
vertical side of the plane. The irradiance incident on the selected surface is S}gUz9ks
projected onto this plane. When the map is displayed, the up vector will point &F1h3q)L
toward the top of the screen.