is almost identical to las2iso except that it can extract elevation contours from much much larger inputs. While las2iso operates in-core and is therefore limited to a maximum of around 20 million points, blast2iso utilizes unique “streaming TIN” technology and can seamlessly process up to 2 billion points. This tool is part of the BLAST extension of LAStools. For more details see the README file.
Below an (academic) video that explains the “streaming TIN” technology that is used to Delaunay triangulate so many points using little main memory.