Normal of a Plane
Plane: sum of
a point and two vectors
P = P1 + a`u + b`v
P - P1 = a`u + b`v
If`n is
orthogonal to`u and`v (n =`u ´`v ) :
`n T · (P - P1) = a`n T ·`u + b`n T ·`v = 0
P1
`u
`v
`u
P1
`v
`n