站长说的很对,补充一下: Qrjo@_+w!
Normal Vector Qi`Lj5;\F
The Normal Vector is a vector in 3D space that is used to orient the projection yS0YWqv]6@
plane for the irradiance map. The plane is defined to be perpendicular to the 5qtZ`1Hq
Normal Vector, and the irradiance incident on the selected surface is projected tjc3;9
onto this plane. When the map is displayed, the normal vector is pointing toward %7 h_D
you. mDz{8N9<FG
Up Vector 'F3Xb
The Up Vector is a vector in 3D space that is used to orient the projection plane z?`&HU Nf
for the irradiance map. The plane is defined so that the Up Vector is parallel to the TB9{e!4
vertical side of the plane. The irradiance incident on the selected surface is O_aZ\28};C
projected onto this plane. When the map is displayed, the up vector will point XL>v$7`#
toward the top of the screen.