站长说的很对,补充一下: #]
GM#.
Normal Vector y*(YZ zF
The Normal Vector is a vector in 3D space that is used to orient the projection 2DC#PX)i
plane for the irradiance map. The plane is defined to be perpendicular to the 8Cqs@<r4Od
Normal Vector, and the irradiance incident on the selected surface is projected 4By-+C*
onto this plane. When the map is displayed, the normal vector is pointing toward 0/gcSW
b
you. k`AJ$\=
Up Vector d$TW](Bby
The Up Vector is a vector in 3D space that is used to orient the projection plane p_AV3
for the irradiance map. The plane is defined so that the Up Vector is parallel to the F:@Ixk?E
vertical side of the plane. The irradiance incident on the selected surface is Na6z,TW
projected onto this plane. When the map is displayed, the up vector will point *@&
"MZ/M
toward the top of the screen.