Project Point onto Line 3D

Problem

Project a point p onto the line through q with direction d in 3D.

The closest point is q + s*d with s = (p - q) . d / (d . d). Return the projected point as a list, or None if d is the zero vector.

Hint

The offset from q must be parallel to d, so rescale d by the signed length.

case 1

in: [[1,1,1],[0,0,0],[1,0,0]]

expected: [1,0,0]

case 2

in: [[2,3,4],[1,1,1],[1,1,1]]

expected: [3,3,3]

case 3

in: [[1,2,3],[1,2,3],[5,0,0]]

expected: [1,2,3]

case 4

in: [[1,2,3],[0,0,0],[0,0,0]]

expected: null

case 5

in: [[0,0,5],[0,0,1],[0,0,2]]

expected: [0,0,5]

Starter codePython

def project_point_line_3d(p, q, d):
    # Your code here
    pass

5 test cases · run your code against them in the editor