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### Aruco markers with openCv, get the 3d corner coordinates?

I am detecting a printed Aruco marker using opencv 3.2:

aruco::estimatePoseSingleMarkers(corners, markerLength, camMatrix, distCoeffs, rvecs,tvecs);


this returns a translation and rotation vector for the marker. What I need, is the 3d coordinates for each corner of the marker.

As i know the marker length, i could do something like

corner1 = tvecs[0] - markerlength /2;
corner2 = tvecs[0] + markerlength /2;
....


But is there an better way? Or an existing function?

How can i return the 3d corner coordinates of a marker, in world space (where the camera is at 0,0,0)?

Thanks!