站长说的很对，补充一下： 8>9MeDE
Normal Vector P:WxhO /
The Normal Vector is a vector in 3D space that is used to orient the projection }KYOde@
plane for the irradiance map. The plane is defined to be perpendicular to the IR{XL \WF
Normal Vector, and the irradiance incident on the selected surface is projected b k1.H@8
onto this plane. When the map is displayed, the normal vector is pointing toward =
c1>ja
you. 5|7<ZL 3
Up Vector K^h9\< w
The Up Vector is a vector in 3D space that is used to orient the projection plane njaKU?6%d2
for the irradiance map. The plane is defined so that the Up Vector is parallel to the l_4 ^TYF
vertical side of the plane. The irradiance incident on the selected surface is vw$b]MO!
projected onto this plane. When the map is displayed, the up vector will point j rxq558
toward the top of the screen.
