FEA & Mechanical Simulation

When a stress, thermal, or modal answer matters more than a render. Pairs with Mechanical CAD and Programmatic CAD. For circuit-level / EM simulation see Circuit Simulation.

FEA solvers (open source)

• ★ CalculiX — open-source FEA solver with an Abaqus-style input deck; the engine FreeCAD's FEM workbench drives by default. GPL. Static, modal, dynamic, thermal, contact.
• ★ Code_Aster — EDF (the French utility); enormous capability; steep learning curve; GPL.
• Elmer FEM — Finnish; multiphysics (mechanical, thermal, EM, fluid). GPL.
• FEniCS / DOLFINx — Python-driven PDE / FEA framework for researchers and engineers comfortable writing variational forms. LGPL.
• deal.II — C++ FEA library, very capable, research-grade.
• MoFEM, NGSolve — research-grade; C++/Python.

FEA pre/post (the GUI you'll actually use)

• ★ FreeCAD FEM workbench — the most accessible open-source FEA front end in 2026. Drives CalculiX (default) or Z88 / Elmer; integrates meshing via Gmsh / Netgen. LGPL.
• ★ PrePoMax — free closed-source Windows GUI for CalculiX; many users find it the smoothest CalculiX experience anywhere.
• Salome-Meca — Code_Aster + Salome platform; the canonical Code_Aster GUI.
• CalculiX Launcher / cgx — bare-bones CalculiX UI.
• Mecway — affordable closed-source FEA; great for beam/shell/plate structures.
• Z88 / Z88Aurora — University of Bayreuth FEA; free, GPL-ish.

Commercial / paid

• Ansys Discovery / Ansys Student — free Ansys for students with node caps; not commercial.
• SimScale — browser-based commercial FEA/CFD; free Community plan with public projects.
• Onshape Simulation — built-in (paid plans).
• Fusion 360 Simulation — extension; paid.
• Abaqus / Nastran / MSC — high-end; expensive.
• COMSOL — multiphysics; expensive.

CFD (fluid)

• ★ OpenFOAM — the dominant FOSS CFD solver. GPL. Steep CLI/case-file learning curve.
• SU2 — Stanford open-source CFD; aerospace bias.
• SimScale — see above; free public-projects tier.
• Code_Saturne — EDF's CFD; GPL.
• Basilisk — research-grade adaptive solver.
• paraFoam / ParaView — the standard FOSS post-processor for OpenFOAM and many others.

Meshing

• ★ Gmsh — the standard FOSS meshing tool; CLI / GUI / Python API. GPL.
• Netgen — alternative open-source mesher; pairs with Salome and FreeCAD.
• cfMesh — OpenFOAM-aligned mesher; LGPL community fork.
• Coreform Cubit Learn — free for non-commercial; capable hex meshing.
• Gmsh inside FreeCAD's FEM — the most common path for beginners.

Topology optimization / generative

• TopOpt 99 / TopOpt-101 — Matlab / Python educational topology codes.
• dolfin-adjoint — adjoint-method optimization on top of FEniCS.
• nTopology / nTop — commercial; the dominant generative-design tool in 2026.
• Fusion 360 Generative Design — paid extension.

Visualization / post-processing

• ★ ParaView — the standard FOSS multi-engine visualizer; reads OpenFOAM, CalculiX, Code_Aster output. BSD.
• VisIt — alternative; LLNL.
• ParaView Glance — browser version.

Pick this if…

• Default FOSS structural FEA, beginner-friendly: FreeCAD FEM (CalculiX) or PrePoMax.
• Heavy industrial-grade FOSS structural: Code_Aster + Salome-Meca.
• Multiphysics (thermal + EM + fluid): Elmer or COMSOL (paid).
• CFD, FOSS, willing to invest in learning: OpenFOAM + ParaView.
• CFD without learning case files: SimScale free tier (public projects only).
• Topology optimization: nTop (commercial) or dolfin-adjoint (research/FOSS).
• Just need to mesh a STEP for someone else's solver: Gmsh.