站长说的很对,补充一下: `&D|>tiz
Normal Vector f>W-
The Normal Vector is a vector in 3D space that is used to orient the projection T(t+
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plane for the irradiance map. The plane is defined to be perpendicular to the nq6@6GRG
Normal Vector, and the irradiance incident on the selected surface is projected ~NQ72wph{
onto this plane. When the map is displayed, the normal vector is pointing toward pgOQIzu
you. %KmiH
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Up Vector o| #Qu8Lk
The Up Vector is a vector in 3D space that is used to orient the projection plane F )W:
for the irradiance map. The plane is defined so that the Up Vector is parallel to the p4'G$]#
vertical side of the plane. The irradiance incident on the selected surface is XzIl`eH
projected onto this plane. When the map is displayed, the up vector will point -?mfE+kt
toward the top of the screen.