站长说的很对,补充一下: \awkt!Wa
Normal Vector Yhm veV
The Normal Vector is a vector in 3D space that is used to orient the projection 8tna<Hx
plane for the irradiance map. The plane is defined to be perpendicular to the t#y,9>6
Normal Vector, and the irradiance incident on the selected surface is projected hmG8
{h/
onto this plane. When the map is displayed, the normal vector is pointing toward X%(NI(+x,
you. {.KD#W
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Up Vector +(afO~9
The Up Vector is a vector in 3D space that is used to orient the projection plane (pP.*`JRv
for the irradiance map. The plane is defined so that the Up Vector is parallel to the ONy\/lu|
vertical side of the plane. The irradiance incident on the selected surface is )uR_d=B&
projected onto this plane. When the map is displayed, the up vector will point $Zw+"AA
toward the top of the screen.