站长说的很对,补充一下: Y.g59X!Ub2
Normal Vector cSXwYZDx?
The Normal Vector is a vector in 3D space that is used to orient the projection >-H{Z{VDd
plane for the irradiance map. The plane is defined to be perpendicular to the `s\?w5[
Normal Vector, and the irradiance incident on the selected surface is projected 0NS<?p~_S
onto this plane. When the map is displayed, the normal vector is pointing toward bbrXgQ`s+w
you. -$\+'
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Up Vector NR`C(^}
The Up Vector is a vector in 3D space that is used to orient the projection plane o4|M0
for the irradiance map. The plane is defined so that the Up Vector is parallel to the W[Ls|<Q
vertical side of the plane. The irradiance incident on the selected surface is &YF^j2
projected onto this plane. When the map is displayed, the up vector will point XUz3*rfs
toward the top of the screen.