站长说的很对，补充一下： <80M$a
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Normal Vector etk|%%J
The Normal Vector is a vector in 3D space that is used to orient the projection m`jGBSlw_
plane for the irradiance map. The plane is defined to be perpendicular to the 4x.I "eW~&
Normal Vector, and the irradiance incident on the selected surface is projected tR_DN
onto this plane. When the map is displayed, the normal vector is pointing toward !ED,'d%J
you. S4OOm[8
Up Vector T;i+az{N:V
The Up Vector is a vector in 3D space that is used to orient the projection plane ~O
4@b/!4
for the irradiance map. The plane is defined so that the Up Vector is parallel to the HN<e)E38
vertical side of the plane. The irradiance incident on the selected surface is ~!_UDD
projected onto this plane. When the map is displayed, the up vector will point Az/P;C=
toward the top of the screen.
