站长说的很对,补充一下: d]bM,`K* 6
Normal Vector Wa {()Cz
The Normal Vector is a vector in 3D space that is used to orient the projection sD_"
plane for the irradiance map. The plane is defined to be perpendicular to the aNcuT,=(?8
Normal Vector, and the irradiance incident on the selected surface is projected !`UHr]HJ
onto this plane. When the map is displayed, the normal vector is pointing toward ICbT{Mla
you. >wPMJ>
2
Up Vector ~4MUac^w
The Up Vector is a vector in 3D space that is used to orient the projection plane '5:P,1tWU
for the irradiance map. The plane is defined so that the Up Vector is parallel to the 4pkTOQq_tQ
vertical side of the plane. The irradiance incident on the selected surface is (K"8kQLY
projected onto this plane. When the map is displayed, the up vector will point Gd=l{~
toward the top of the screen.