Calculix is a free and open source finite element analysis application that uses a similar input format to ABAQUS. It has an implicit and explicit solver (CCX) written by Guido Dhondt and a pre and post processor (CGX) written by Klaus Wittig. The original software was written for the Linux operating system. Convergent Mechanical Solutions has ported the application to the Windows operating system. Literature Guido Dhondt: "The Finite Element Method for Three-Dimensional Thermomechanical Appl… (More on Calculix)