站长说的很对,补充一下: le6eorK8
Normal Vector N!<X%Ym
The Normal Vector is a vector in 3D space that is used to orient the projection ~J
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plane for the irradiance map. The plane is defined to be perpendicular to the O6ltGtF
Normal Vector, and the irradiance incident on the selected surface is projected o;>qsn8
onto this plane. When the map is displayed, the normal vector is pointing toward ;rl61d}NH#
you. C|]Zpn#{K
Up Vector ?gCP"~
The Up Vector is a vector in 3D space that is used to orient the projection plane 4@0Z<8Mo
for the irradiance map. The plane is defined so that the Up Vector is parallel to the &D&U!3~(
vertical side of the plane. The irradiance incident on the selected surface is rd,!-w5
projected onto this plane. When the map is displayed, the up vector will point HC"yC;_
toward the top of the screen.