PrePoMax and CalculiX — The Complete Guide: Free Finite Element Analysis With a Friendly Interface
CalculiX is an open-source finite element solver with an input syntax very similar to Abaqus. Its historical problem was the interface. PrePoMax, developed at the University of Maribor in Slovenia, solved that: a modern Windows interface in which you build the whole analysis with the mouse — from geometry to results — while CalculiX computes in the background.
CalculiX
CalculiX Project
Open-source FEA with syntax close to Abaqus. The solver behind the FreeCAD FEM workbench.
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PrePoMax
University of Maribor
Full graphical front end for CalculiX — meshing, materials, loads and results in one window.
Get it from the vendorWhat you can analyse
- Linear static — stresses and displacements in parts, brackets, connection details and plates.
- Nonlinearity — material plasticity, large displacements and contact between parts, including friction.
- Natural frequencies and buckling — modal analysis and linear buckling.
- Heat transfer — steady and transient, and thermo-mechanical coupling.
- Topology optimisation — reducing part weight along the load paths.
The workflow
1. Import geometry as STEP — for example from FreeCAD. 2. Build a mesh with element size settings and local refinement near holes and corners. 3. Set material, supports and loads. 4. Define contacts if there are several parts. 5. Run. 6. Review Von Mises stresses, displacements and reaction forces, and check that the reactions add up to the load.
FreeCAD
FreeCAD Project
Open-source parametric 3D modeller with workbenches for solid modelling, FEM, drafting and BIM.
Get it from the vendorWhat's missing
PrePoMax runs on Windows only. It lacks advanced material models on the level of Abaqus, has no convenient structural elements for analysing large structures (a dedicated structural analysis tool is better for that), and has no code checks. Support is community-based. And in any FEA, mesh quality and boundary conditions decide whether the result is reliable, so a mesh convergence check is a must.
Who it suits
Mechanical and structural engineers who need to check a part or a connection detail, product designers, students who want to learn FEA on a real tool, and small offices that need an occasional strength check without an ANSYS licence.
Alternatives and companion tools
If you work on Linux or want more capability — Code_Aster with SALOME. Elmer FEM for multiphysics problems. Gmsh for advanced meshing. And for nonlinear structural and earthquake analysis — OpenSees.
Code_Aster
EDF
EDF industrial finite element solver — nonlinear, dynamic and thermo-mechanical, open source.
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SALOME
CEA / EDF / OPEN CASCADE
Geometry, meshing and post-processing platform for FEA, around external solvers.
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Elmer FEM
CSC — IT Center for Science, Finland
Multiphysics FEA — solids, flow, heat and electromagnetics — with its own graphical interface.
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Gmsh
Gmsh Project
FEA mesh generator with built-in geometry and scripting — standard infrastructure for open numerical work.
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OpenSees
Pacific Earthquake Engineering Research Center, UC Berkeley
Nonlinear and dynamic structural analysis driven by scripts, from the earthquake engineering world.
Get it from the vendorBottom line
PrePoMax with CalculiX is the easiest way to start doing real finite element analysis for free — with an interface that feels like commercial software and a solver also used in industry.