站长说的很对,补充一下: smIZ:L%
Normal Vector **_VNDK+
The Normal Vector is a vector in 3D space that is used to orient the projection a}i{b2B
plane for the irradiance map. The plane is defined to be perpendicular to the &I'~:nWpt
Normal Vector, and the irradiance incident on the selected surface is projected 3 [SN[faS
onto this plane. When the map is displayed, the normal vector is pointing toward reu[}k ~
you. 0WF(Ga/o
Up Vector >B8)Wb:
The Up Vector is a vector in 3D space that is used to orient the projection plane {)4Vv`n
for the irradiance map. The plane is defined so that the Up Vector is parallel to the qE$.a[
vertical side of the plane. The irradiance incident on the selected surface is Wn0r[h5t
projected onto this plane. When the map is displayed, the up vector will point px//q4U
toward the top of the screen.