OpenFOAM vs Step

OpenFOAM is a free, open-source computational fluid dynamics toolbox for simulating fluid flow, heat transfer, and related physical processes. It provides pre-processing, mesh generation, solvers for different flow and physics problems, and post-processing tools. Built-in utilities include blockMesh and snappyHexMesh, and it can convert meshes from external formats. ParaView visualization is supported through the paraFoam launcher, reader modules, VTK conversion, and VTK output during simulations. OpenFOAM runs on Linux, macOS, and Windows, and supports self-hosted use. Its current release is v2606, released on 26 June 2026; GPU offloading is available as a compile-time option, with that work on a separate development track. It is distributed under the GNU General Public Licence. OpenCFD offers a one-year support package for installation, fixes, updates, CFD assistance, and code customization, subject to a yearly service-hours maximum. It does not respond to support queries without a prior package. Training courses are also offered, with prices provided through a schedule or enquiry process.

Step is a free Linux desktop application for exploring physical systems through interactive simulations. Users can change body and force properties while a simulation runs. Supported models include two-dimensional classical mechanics, molecular dynamics, sound waves, and deformable bodies, with particles, damped springs, gravitational and Coulomb forces, rigid bodies, and collision handling. Step calculates unit conversions, expressions, error propagation, and solver error estimates. Explicit and implicit solvers reach 8th order, with optional adaptive timesteps; most require GSL. Graph, meter, and tracer tools visualize results, while a controller changes properties using keyboard shortcuts. Tutorials, example experiments, object information, and an integrated Wikipedia browser provide learning material. More examples can be downloaded through KNewStuff. Expression calculations such as unit conversion require libqalculate. Step is GPL-2.0+ software, and its StepCore library can be used separately. The listed release is Step 26.08.2, released 2026-10-08.