nanoCAD

QCAD is a free, open-source application for computer-aided drafting (CAD) in two dimensions (2D). With QCAD you can create technical drawings such as plans for buildings, interiors, mechanical parts or schematics and diagrams. QCAD works on Windows, macOS, and Linux. The source code of QCAD is released under the GPL version 3 (GPLv3), a popular Open Source license. QCAD was designed with modularity, extensibility and portability in mind. But what people notice most often about QCAD is its intuitive user interface. QCAD is an easy-to-use but powerful 2D CAD system for everyone. You don't need any CAD experience to get started with QCAD immediately. Construction and modification of points, lines, arcs, circles, ellipses, splines, polylines, texts, dimensions, hatches, fills, and raster images. Very complete and extremely powerful ECMAScript (JavaScript) scripting interface. Various powerful entity selection tools.

By performing structural analyses on fully featured CAD assemblies within minutes, SimSolid is the game-changing simulation technology for designers, engineers, and analysts. It eliminates geometry preparation and meshing: the two most time-consuming, expertise-extensive and error-prone tasks performed in a conventional structural simulation. Multiple design scenarios can be simulated quickly under real-life conditions. Early CAD models, in any common format, can be used. SimSolid tolerance of imprecise geometry means that, unlike CAD-embedded simulation tools, there is no need to simplify complex geometries before analyzing designs. SimSolid supports all typical connections (bolt/nut, bonded, welds, rivets, sliding) and analysis of linear static, modal, thermal properties, along with more complex coupled, nonlinear, transient dynamic effects.