0
$\begingroup$

I have a list of 3D points defined by Cartesian coordinates, i.e. [(x1,y1,z1), (x2,y2,z2), ..., (xn,yn,zn)]. I want to project them to a 2D plane which has origin in the center (0,0,0) but which is rotated by polar angle theta, and azimuthal angle phi (*).

As far as I understand I need some kind of 3x2 matrix that when multiplied with my points matrix nx3 will give me my projection in 2D.

nx3 matrix-multiply 3x2 = nx2

How to calculate this matrix if I know the angles of the plane rotation?

If it helps here's a quick explanation what I'm trying to do. I have a 3d object consisting of point cloud, which is centered in the origin and I want to calculate how it looks from a camera placed on different points that are on equal distance from the origin, looking directly toward the origin, and with light coming from the camera and toward the origin.

(*) I'm not sure does does those two angle define the plane in a unique way.

$\endgroup$
  • 1
    $\begingroup$ Do you mean orthographic projection? If that is the case then find by what rotation matrix do you need to transform the xy plane for example (normal=(0,0,1)) to get to the plane in your problem. Then multiply each point with the transposed rotation matrix and drop the third coordinate. $\endgroup$ – lightxbulb Jun 24 at 11:03
  • $\begingroup$ @lightxbulb I think so but I'm not sure. Could you give me an example for say projecting a point A(2,1, 3) which I need to project to plane with 60 degrees polar angle and 20 degrees azimuth angle. $\endgroup$ – slobodan.blazeski Jun 24 at 11:10
  • $\begingroup$ Compute it yourself and see if that is what you want. $\endgroup$ – lightxbulb Jun 24 at 11:47

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.