Cutting one 3D point cloud using the other 3D point cloud (TerraScan).

Hello

I have 2 3D point clouds - 1.las and 2.las and I would like to recive another 3D point cloud - 3.las. The 3D point cloud 2.las is the part of 1.las. Now I need to "cut off" the stuff from 2.las 3D point cloud out of 3D point cloud 1.las. Do anynone know how to do it fast? If my question is a little bit messy as an example - imagine I have a trolley with 20 apples inside (1.las) and now I need to cut off only 5 aplles which are inside the trolley (2.las) and receive 3.las with only the trolley and 15 apples (2.las minus 1.las).

Thank you very much for any help