SOLVESPACE is a free (GPLv3) parametric 3d CAD tool. Modeling 3d parts, drawing with extrudes, revolves, helixes and Boolean (union/difference/intersection) operations. Modeling 2d parts, draw the part as a single section, and export DXF, PDF, SVG; use 3d assembly to verify fit. 3D-printed parts, export the STL or other triangle mesh expected by most 3d printers. Preparing CAM data, export 2d vector art for a waterjet machine or laser cutter; or generate STEP or STL, for import into third-party CAM software for machining. Mechanism design, use the constraint solver to simulate planar or spatial linkages, with pin, ball, or slide joints. Plane and solid geometry, replace hand-solved trigonometry and spreadsheets with a live dimensioned drawing. Sketch sections using lines, rectangles, datum lines and points. Sketch circles, arcs of a circle, datum circles, cubic Bezier segments, C2 interpolating splines, and more.