站长说的很对,补充一下: /dt'iai~l
Normal Vector FAP1Bm
The Normal Vector is a vector in 3D space that is used to orient the projection )uIHonXU
plane for the irradiance map. The plane is defined to be perpendicular to the W(&9S[2
Normal Vector, and the irradiance incident on the selected surface is projected vV+>JM6<K
onto this plane. When the map is displayed, the normal vector is pointing toward &yQM8J~
you. {_5PN^J
Up Vector L}5IX)#gH
The Up Vector is a vector in 3D space that is used to orient the projection plane Lmw{ `R
for the irradiance map. The plane is defined so that the Up Vector is parallel to the HRZ3}8Qj
vertical side of the plane. The irradiance incident on the selected surface is d( +E0
projected onto this plane. When the map is displayed, the up vector will point um$ K^
toward the top of the screen.