站长说的很对,补充一下: Pfh mo $
Normal Vector "~nZ GiK
The Normal Vector is a vector in 3D space that is used to orient the projection Smh,zCc>s
plane for the irradiance map. The plane is defined to be perpendicular to the rjP/l6
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Normal Vector, and the irradiance incident on the selected surface is projected NlqImM=r,
onto this plane. When the map is displayed, the normal vector is pointing toward sT.ss$HY9,
you. iCoX&"lb
Up Vector QPx^_jA
The Up Vector is a vector in 3D space that is used to orient the projection plane maZ)cW?
for the irradiance map. The plane is defined so that the Up Vector is parallel to the
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vertical side of the plane. The irradiance incident on the selected surface is 0J|3kY-n>
projected onto this plane. When the map is displayed, the up vector will point :m;p:l|W
toward the top of the screen.