站长说的很对，补充一下： Jk|DWZ
Normal Vector d,meKQ n
The Normal Vector is a vector in 3D space that is used to orient the projection 7bGt'gvv
plane for the irradiance map. The plane is defined to be perpendicular to the SV95 g @
Normal Vector, and the irradiance incident on the selected surface is projected kMEXg zl
onto this plane. When the map is displayed, the normal vector is pointing toward t^6ams$
you. Ha ZV 7
Up Vector WyQ8}]1 b
The Up Vector is a vector in 3D space that is used to orient the projection plane jL 3
*m
for the irradiance map. The plane is defined so that the Up Vector is parallel to the I) *J,hs1
vertical side of the plane. The irradiance incident on the selected surface is J-
l[dC
projected onto this plane. When the map is displayed, the up vector will point zC[LcC*+J
toward the top of the screen.
