站长说的很对,补充一下: 3H,>[&d
Normal Vector a,\GOy(q{
The Normal Vector is a vector in 3D space that is used to orient the projection d4A3DTW
plane for the irradiance map. The plane is defined to be perpendicular to the /G#W/Q
Normal Vector, and the irradiance incident on the selected surface is projected ^j]"5@f
onto this plane. When the map is displayed, the normal vector is pointing toward =8x-+u5}rK
you. ]8EkZC
Up Vector N"/be
The Up Vector is a vector in 3D space that is used to orient the projection plane f9J]-#I if
for the irradiance map. The plane is defined so that the Up Vector is parallel to the rcG-Vf@
vertical side of the plane. The irradiance incident on the selected surface is O]\eMM&
projected onto this plane. When the map is displayed, the up vector will point E0"DHjR
toward the top of the screen.