'Check if a point is on a 3d line?

I know how to check if a point is on a 2d line or not, but I'd like to do this in 3D. Any ideas?

        // slope from point 1 to point 3
        var p13:Number = (Math.atan2 (end.x - start.x, end.y - start.y)) * toDegrees;

        // slope from point 1 to point 2 -- matches?
        var p12:Number = (Math.atan2 (point.x - start.x, point.y - start.y)) * toDegrees;

        return Math.round(p12) == Math.round(p13);

3d geometry points angle

Solution 1:^[1]

A point can never be 'on' a line in real coords. what you need to do is calculate the distance to the closest point to the line and decide if this is close enough for you.

Solution 2:^[2]

The equation of a line is

v(t) = v0 + t*dir

Where v0 is some point on a line and dir is it's direction. Simply check if your point match this linear equation with enough accuracy

Sources

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Source: Stack Overflow

Solution	Source
Solution 1	Martin Beckett
Solution 2	Andrew

'Check if a point is on a 3d line?

Solution 1:[1]

Solution 2:[2]

Sources

Related Questions

Solution 1:^[1]

Solution 2:^[2]