站长说的很对,补充一下: "tjLc6Xl^
Normal Vector {@! Kx`(:
The Normal Vector is a vector in 3D space that is used to orient the projection i)
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plane for the irradiance map. The plane is defined to be perpendicular to the p'7*6bj1
Normal Vector, and the irradiance incident on the selected surface is projected 5DOBsf8Jo
onto this plane. When the map is displayed, the normal vector is pointing toward qd3Q}Lk
you. Twn4lG4~
Up Vector =K'cM=WM6
The Up Vector is a vector in 3D space that is used to orient the projection plane 8
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for the irradiance map. The plane is defined so that the Up Vector is parallel to the q9w~A-Oh`1
vertical side of the plane. The irradiance incident on the selected surface is ^7zu<lX
projected onto this plane. When the map is displayed, the up vector will point 8k
q5ud
toward the top of the screen.