站长说的很对,补充一下: 1DAU*^-
Normal Vector @#W4?L*D
The Normal Vector is a vector in 3D space that is used to orient the projection J>T98y/))
plane for the irradiance map. The plane is defined to be perpendicular to the ub>:dNBN
Normal Vector, and the irradiance incident on the selected surface is projected 4<UAT|L^`
onto this plane. When the map is displayed, the normal vector is pointing toward 5ta;C G
you. .EHq.cde
Up Vector &)tv4L&
The Up Vector is a vector in 3D space that is used to orient the projection plane 3zKeN:w
for the irradiance map. The plane is defined so that the Up Vector is parallel to the ~:Z|\a58j
vertical side of the plane. The irradiance incident on the selected surface is #Ox@[Z1I
projected onto this plane. When the map is displayed, the up vector will point
C&qo$C
toward the top of the screen.