站长说的很对,补充一下: (0r3/t?DQ
Normal Vector ~"H,/m%2o
The Normal Vector is a vector in 3D space that is used to orient the projection _ QI\
plane for the irradiance map. The plane is defined to be perpendicular to the BLdvyVFx
Normal Vector, and the irradiance incident on the selected surface is projected l"T44CL;
onto this plane. When the map is displayed, the normal vector is pointing toward / }X1W
you. (O?.)jEW(.
Up Vector W]1)zO
The Up Vector is a vector in 3D space that is used to orient the projection plane . B9iLI
for the irradiance map. The plane is defined so that the Up Vector is parallel to the Jb@V}Ul$
vertical side of the plane. The irradiance incident on the selected surface is X*XZb F"=
projected onto this plane. When the map is displayed, the up vector will point ]L $\
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toward the top of the screen.