站长说的很对,补充一下: gLv|Hu7
Normal Vector ;9r
Z{'i+|
The Normal Vector is a vector in 3D space that is used to orient the projection [vki^M5i|Z
plane for the irradiance map. The plane is defined to be perpendicular to the u#5/s 8
Normal Vector, and the irradiance incident on the selected surface is projected v-6"*EP
onto this plane. When the map is displayed, the normal vector is pointing toward /UeLf$%ZW
you. -1Y9-nn[m
Up Vector a] :tn:q
The Up Vector is a vector in 3D space that is used to orient the projection plane YArNJ5z=
for the irradiance map. The plane is defined so that the Up Vector is parallel to the iO=xx|d
vertical side of the plane. The irradiance incident on the selected surface is gr %8
O-n
projected onto this plane. When the map is displayed, the up vector will point ?]gZg[
toward the top of the screen.