站长说的很对,补充一下: "Ot{^_e
Normal Vector 4$Pr|gx
The Normal Vector is a vector in 3D space that is used to orient the projection T.@sq
plane for the irradiance map. The plane is defined to be perpendicular to the k7T
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Normal Vector, and the irradiance incident on the selected surface is projected !!+Da>
onto this plane. When the map is displayed, the normal vector is pointing toward P6we(I`"2
you. if@,vc
Up Vector 4Hd Si
The Up Vector is a vector in 3D space that is used to orient the projection plane ND*]gM
for the irradiance map. The plane is defined so that the Up Vector is parallel to the ^&m?qKN8
vertical side of the plane. The irradiance incident on the selected surface is STB-guia5
projected onto this plane. When the map is displayed, the up vector will point +H}e)1^I
toward the top of the screen.