站长说的很对,补充一下: V5m4dQ>t
Normal Vector U:p<pTnMR
The Normal Vector is a vector in 3D space that is used to orient the projection ">|fB&~A
plane for the irradiance map. The plane is defined to be perpendicular to the Xfe,ZC)
Normal Vector, and the irradiance incident on the selected surface is projected [W`
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onto this plane. When the map is displayed, the normal vector is pointing toward VCtj8hKDr
you. lO[[iMHl<
Up Vector ka655O/)&
The Up Vector is a vector in 3D space that is used to orient the projection plane ]wZG4A
for the irradiance map. The plane is defined so that the Up Vector is parallel to the -B'<*Y
vertical side of the plane. The irradiance incident on the selected surface is @xR=bWY
projected onto this plane. When the map is displayed, the up vector will point M,zUg_ @
toward the top of the screen.