The most convenient program for: loading and drawing XYZ files of points, triangulation, contour lines and color-filled contour maps. You can also draw 4D points cloud and process hundreds of thousands of points or triangles, even on less powerful PCs.
You don't need another CAD system. RTOPO LT has its own CAD system.
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RTOPO LT is the reduced version of the full RTOPO Hydrology CAD for topography, which has in addition: editing of XYZ files of points, cross-sections and longitudinal profile, simulation of rainwater runoff, projection of a curve on triangulation, calculation of the volume between surfaces formed by 3DFACE and the intersection and division of 2 sets of 3DFACE.