CalculiX is a free and open-source finite-element analysis application that uses an input format similar 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 has ported the application to the Windows operating system.
The pre-processor component of CalculiX can generate grid data for the computational fluid dynamics programs duns, ISAAC and OpenFOAM. It can also generate input data for the commercial FEM programs Nastran, Ansys and Abaqus. The pre-processor can also generate mesh data from STL files. 
2.1719 Aug 2020 21:16