takes as input a LAS/LAZ/TXT file and a SHP/TXT file with one or many polygons (e.g. building footprints or flight lines), clips away all the points that fall outside all polygons (or inside some polygon), and stores the surviving points to the output LAS/LAZ/TXT file. Instead of clipping the points they can also be classified. For more details see the README file. Below some typical results: