站长说的很对,补充一下: {_>XsB
Normal Vector UN<$F yb
The Normal Vector is a vector in 3D space that is used to orient the projection 7iy 2V;}
plane for the irradiance map. The plane is defined to be perpendicular to the r{*Qsaw
Normal Vector, and the irradiance incident on the selected surface is projected #.FhN x
onto this plane. When the map is displayed, the normal vector is pointing toward {#t7lV'4
you. a'q&[08
Up Vector iqF|IVPoi
The Up Vector is a vector in 3D space that is used to orient the projection plane 7#HSe#0J
for the irradiance map. The plane is defined so that the Up Vector is parallel to the n1x3q/~
vertical side of the plane. The irradiance incident on the selected surface is i1{)\/f3
projected onto this plane. When the map is displayed, the up vector will point MTR+|I3V
toward the top of the screen.