cloudcompare

CloudCompare is a 3D point cloud (and triangular mesh) processing software.
Originally designed to perform comparison between two dense 3D points clouds
or between a point cloud and a triangular mesh, it has been extended to a
more generic point cloud processing software, including many advanced
algorithms (registration, resampling, color/normal/scalar fields handling,
statistics computation, sensor management, interactive or automatic
segmentation, display enhancement, etc.).