站长说的很对,补充一下: :@p`E}1r{
Normal Vector c.XLEjV|
The Normal Vector is a vector in 3D space that is used to orient the projection Kzmgy14o
plane for the irradiance map. The plane is defined to be perpendicular to the InDR\=o
Normal Vector, and the irradiance incident on the selected surface is projected y}3V3uqK
onto this plane. When the map is displayed, the normal vector is pointing toward EXzY4D ^
you. 4C2 Dwj
Up Vector *r_.o;6
The Up Vector is a vector in 3D space that is used to orient the projection plane E6G^?k~q
for the irradiance map. The plane is defined so that the Up Vector is parallel to the BE U[M
vertical side of the plane. The irradiance incident on the selected surface is jXdn4m/O
projected onto this plane. When the map is displayed, the up vector will point 68d @By
toward the top of the screen.