CloudCompare is a 3D point cloud (and triangular mesh) processing software. It has been originally designed to perform comparison between two 3D points clouds (such as the ones obtained with a laser scanner) or between a point cloud and a triangular mesh. It relies on a specific octree structure that enables great performances in this particular function. It was also meant to deal with huge point clouds (typically more than 10 millions points, and up to 120 millions with 2 Gb of memory).
CloudCompare has an easy to use graphical interface. Point clouds can be visualized and operations like transformatons, subsampling or primitive fitting can be applied. When multiple point clouds are loaded, similarities between point clouds can be visualized or point clouds can be registered automatically using ICP (iterative closest point algorithm).