MPTRAC vs Step
MPTRAC
slcs-jsc.github.ioStep
apps.kde.orgSide by side
| Figure | MPTRAC | Step |
|---|---|---|
| Price from | Free | Free |
| Free plan | Yes | Yes |
| Free trial | — | — |
| Open source | — | — |
| Web | Yes | — |
| Linux | Yes | Yes |
| Self-hosted | Yes | — |
| Plans published | 2 | 1 |
| Spec score · Physics Simulation Software | 8.7 (#7) | 8.2 (#22) |
| Authoring tools | No | Yes |
| Delivery mode | hybrid | desktop |
| Free plan | Yes | Yes |
| Lesson library | No | Yes |
| License | The repository states that MPTRAC is distributed under the GNU General Public License v3.0. | Step is listed under the GPL-2.0+ license. |
| Purpose | MPTRAC is a Lagrangian particle dispersion model for analyzing atmospheric transport in the free troposphere and stratosphere. | Step is an interactive physical simulator for exploring the physical world through simulations. |
| Support | The project directs questions, support, and collaboration inquiries to Dr. Lars Hoffmann at the Jülich Supercomputing Centre. | Help is available through the Step Handbook, KDE forum, the kde-edu mailing list, and the #kde-edu Libera.chat channel. |
| 3D visuals | Yes | No |
Plans
In their own words
MPTRAC
MPTRAC is a Lagrangian particle dispersion model for studying atmospheric transport in the free troposphere and stratosphere. It calculates forward and backward air-parcel trajectories from meteorological wind fields, with stochastic diffusion, subgrid wind variation and mixing between parcels. Optional process parameterizations cover convection, sedimentation, decay, gas-phase and aqueous-phase chemistry, and wet and dry deposition. Listed research applications include long-range pollutant transport, volcanic ash dispersion, tracer experiments and atmospheric chemistry.
The browser-based Web Runner can configure, run and visualize simulations, then download results without local installation. It is limited to 10,000 air parcels, 30 days and 10 minutes of model runtime. The model needs meteorological input, normally netCDF files on a regular pressure, longitude and latitude grid. MPTRAC supports hybrid MPI, OpenMP and OpenACC parallelization, and offers visualization interfaces for Gnuplot and ParaView. It is GPL-3.0 software for Linux, self-hosted and web use; listed pricing includes free.
Step
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.