This is a simple utility for estimating the rigid transformation that aligns two sets of 3D point clouds, given 3 (or more) point matches.
Input: two sets of 3D point clouds (P1 and P2)
Output: homogeneous transformation that aligns the two clouds
1- point i in the first point cloud corresponds to point i in the second cloud
2- the transformation is rigid (i.e. only a rotation and a translation)
3- you need at least 3 (non-degenerate) point matches (i.e. they don't lie on a straight line)
The math is basic and well-known. The point of this upload is just to save the little bit of time it would've taken you to code it yourself.
Reference: "Computer Vision, a modern approach" by Forsyth and Ponce
1- Click3dPoint (on the File Exchange) to manually find a few point correspondences
2- ICP (e.g. Matlat implementation by A. Mian)