Line through two points

Goal: given two points in homogeneous coordinates, find the homogeneous equation of the line through these points, that is, the vector N in the equation

Homogeneous form of a point = 3D vector from the origin to the point.

z=1

z

x

y

N

p1

p2

Line through 2 points =

intersection of the plane

spanned by two lines with

the plane z=1

Normal to that plane (same

as N in the line equation):

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