RTOPO - CAD for Topography, editing 3D points, triangulation, isolines, sections.
Together with RTOPO, is distributed the RCAD CAD system. It provides OpenGL real-time orbit, pan, zoom, shading, lighting and motion path animation. RCAD is similar with other popular CAD systems and can load and save DXF files. It has entries in the command text area, graphics area, menus and toolbars. It has commands for drawing and modification. RCAD can also run scripts and can be called from other programs.