站长说的很对,补充一下: ~:)$~g7>b
Normal Vector 4kg9R^0
The Normal Vector is a vector in 3D space that is used to orient the projection .<42-IEc
plane for the irradiance map. The plane is defined to be perpendicular to the CaBTqo
Normal Vector, and the irradiance incident on the selected surface is projected VY _(0
onto this plane. When the map is displayed, the normal vector is pointing toward E7_^RWG
you. o
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Up Vector 5[gkGKkf_
The Up Vector is a vector in 3D space that is used to orient the projection plane dIO\ lL
for the irradiance map. The plane is defined so that the Up Vector is parallel to the q]Qgg
vertical side of the plane. The irradiance incident on the selected surface is Op%^dwVG(v
projected onto this plane. When the map is displayed, the up vector will point :{66WSa@Dd
toward the top of the screen.