Moving points around a line

Hi dear users, I have a following question: There are some points (3 coordinates each) which form a center line. I have other points which form a shape and I would like to transfer this coordinates along the line mentioned previously. How can I do this with matlab? Thank you!

[Rik]

Have a read here and here. It will greatly improve your chances of getting an answer.

Answer 1

[Roger Stafford]

I assume that by “to transfer this coordinates along the line” you mean you wish to project each such point in the “shape” orthogonally onto the given center line.

Suppose two points along your “center” line are P1 = [x1,y1,z1] and P2 = [x2,y2,z2], and suppose Q1 = [x3,y3,z3] is a point on your shape. Its orthogonal projection, Q2, onto the line P1P2 is given by:

Q2 = P1 + dot(P2-P1,Q1-P1)/dot(P2-P1,P2-P1)*(P2-P1);

('Orthogonal' means that the line Q2Q1 will be perpendicular to line P2P1.)