站长说的很对,补充一下: ~Q2,~9Dkc
Normal Vector '>Uip+'
The Normal Vector is a vector in 3D space that is used to orient the projection V8947h|&
plane for the irradiance map. The plane is defined to be perpendicular to the {C'9?4&
Normal Vector, and the irradiance incident on the selected surface is projected jRBKy8?[C
onto this plane. When the map is displayed, the normal vector is pointing toward *@E&O^%cO
you. ,R*YI
Up Vector 4"et4Y7
The Up Vector is a vector in 3D space that is used to orient the projection plane F* _ytL
for the irradiance map. The plane is defined so that the Up Vector is parallel to the |>v8yS5
vertical side of the plane. The irradiance incident on the selected surface is l0BYv&tu
projected onto this plane. When the map is displayed, the up vector will point rrrn8b6
toward the top of the screen.