站长说的很对,补充一下: +a;:7[%&
Normal Vector
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The Normal Vector is a vector in 3D space that is used to orient the projection -+O8v;aC'
plane for the irradiance map. The plane is defined to be perpendicular to the {?eD7xL:-
Normal Vector, and the irradiance incident on the selected surface is projected Pf(z0o&
onto this plane. When the map is displayed, the normal vector is pointing toward [&)9|EV
you. :)mV-(+o
Up Vector ob-be2EysH
The Up Vector is a vector in 3D space that is used to orient the projection plane m#'u;GP]k
for the irradiance map. The plane is defined so that the Up Vector is parallel to the ~e'FPVDn
vertical side of the plane. The irradiance incident on the selected surface is +O\6p
projected onto this plane. When the map is displayed, the up vector will point L(AY)gB
toward the top of the screen.