站长说的很对,补充一下: I?f"<5[0
Normal Vector \1=T
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The Normal Vector is a vector in 3D space that is used to orient the projection @Djs[Cs<*
plane for the irradiance map. The plane is defined to be perpendicular to the =L:[cIRrT;
Normal Vector, and the irradiance incident on the selected surface is projected kFS0i%Sr
onto this plane. When the map is displayed, the normal vector is pointing toward lKf Mp1
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Up Vector IetCMp
The Up Vector is a vector in 3D space that is used to orient the projection plane \z2vV+f
for the irradiance map. The plane is defined so that the Up Vector is parallel to the b0y-H/d/}
vertical side of the plane. The irradiance incident on the selected surface is XZF%0g2$b
projected onto this plane. When the map is displayed, the up vector will point Zn?8\
toward the top of the screen.