站长说的很对,补充一下: )^#Zg8L
Normal Vector }eFUw
The Normal Vector is a vector in 3D space that is used to orient the projection G*p.JsZP
plane for the irradiance map. The plane is defined to be perpendicular to the GJfNO-
Normal Vector, and the irradiance incident on the selected surface is projected pytfsVM
onto this plane. When the map is displayed, the normal vector is pointing toward @Hdg-f>y]
you. @_ZWP
Up Vector c;}n=7,>:L
The Up Vector is a vector in 3D space that is used to orient the projection plane B_jI!i{N%o
for the irradiance map. The plane is defined so that the Up Vector is parallel to the 8&hn$~ate
vertical side of the plane. The irradiance incident on the selected surface is NfN6KDd]2L
projected onto this plane. When the map is displayed, the up vector will point *<QL[qyV
toward the top of the screen.