站长说的很对,补充一下: N+h05`
Normal Vector 76wNZv)9
The Normal Vector is a vector in 3D space that is used to orient the projection #{PwEX
!Ct
plane for the irradiance map. The plane is defined to be perpendicular to the jn:_2g[
Normal Vector, and the irradiance incident on the selected surface is projected pF4Z4?W
onto this plane. When the map is displayed, the normal vector is pointing toward :nQlS
you. i'7+
?YL
Up Vector Qr9;CVW
The Up Vector is a vector in 3D space that is used to orient the projection plane t*=[RS*
for the irradiance map. The plane is defined so that the Up Vector is parallel to the ](A2,F
9(U
vertical side of the plane. The irradiance incident on the selected surface is xC,x_:R`
projected onto this plane. When the map is displayed, the up vector will point @phVfP"M
toward the top of the screen.