站长说的很对,补充一下: kM4z
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Normal Vector *:d``L
The Normal Vector is a vector in 3D space that is used to orient the projection BMO,eQcB
plane for the irradiance map. The plane is defined to be perpendicular to the &Qda|
Normal Vector, and the irradiance incident on the selected surface is projected 5'f_~>1Wt
onto this plane. When the map is displayed, the normal vector is pointing toward &TRKd)w d
you. <2@t~9
Up Vector (BtU\f#d
The Up Vector is a vector in 3D space that is used to orient the projection plane 1J1Jp|j.
for the irradiance map. The plane is defined so that the Up Vector is parallel to the P=EZ6<c3&
vertical side of the plane. The irradiance incident on the selected surface is V0m1>{
projected onto this plane. When the map is displayed, the up vector will point i7T#WfF
toward the top of the screen.