站长说的很对，补充一下： ?gSk%]S/!
Normal Vector `R} D@
The Normal Vector is a vector in 3D space that is used to orient the projection N ".-]bB
plane for the irradiance map. The plane is defined to be perpendicular to the v!;E1
Normal Vector, and the irradiance incident on the selected surface is projected (VPT% l6
onto this plane. When the map is displayed, the normal vector is pointing toward O ).1>
you. \w
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Up Vector o3;u*f0rWn
The Up Vector is a vector in 3D space that is used to orient the projection plane c-INVA)
for the irradiance map. The plane is defined so that the Up Vector is parallel to the /WDz;, X
vertical side of the plane. The irradiance incident on the selected surface is C/P,W >8
projected onto this plane. When the map is displayed, the up vector will point x*#F|N4~',
toward the top of the screen.
