RTOPO is a simple, powerful and inexpensive CAD software for topography. You can do triangulation, isolines, color-filled contour maps, sections, intersections, volume, editing XYZ files and much more. You can represent 4D points cloud and process hundreds of thousands of points or triangles, even on less powerful PCs. You can also simulate rainwater runoff. You can thus identify the watershed, the flooded areas, the speed and level of the water. It also contains the program "3D CNC milling from DXF + VDAFS to DXF, trial version". The trial version runs only 10 times, can't print or save files and has limitations on some commands!