Sketch structures and instantly explore forces, stresses, deformations, and topology optimisation.
ForcePAD is an open-source, sketch-based 2D finite element analysis tool for structural mechanics education and experimentation. Draw a structural shape like in a paint program, add loads and supports, and inspect the finite element response interactively.
Download | Documentation | Quick start | Examples | Videos
Media placeholder: add a 5-10 second animated GIF here showing the complete workflow: sketch a beam, add supports, add a force, switch to Action mode, and move the force while the stresses update.
- Sketch-based modelling: create structures with brushes, fill tools, lines, rectangles, and ellipses.
- Immediate feedback: view displacements, principal stresses, and von Mises stresses without a heavyweight CAD workflow.
- Interactive exploration: move and rotate forces while the structural response updates.
- Topology optimisation: run optimisation experiments from an initial design domain.
- Educational focus: designed for teaching finite element analysis, structural mechanics, stress flow, and deformation behaviour.
- Open source: GPL-2 licensed C++ code using Qt, OpenGL, Eigen, and a C++ CALFEM implementation.
- Download the latest release.
- Open ForcePAD and create a new model, or load one of the bundled
.fp2examples. - Use Sketch mode to draw material on the canvas.
- Use Physics mode to add constraints and forces.
- Use Action mode to inspect stresses, displacements, and topology optimisation results.
See the full Quick start in 60 seconds guide for screenshots.
The repository includes sample .fp2 models under bin/release/samples/, including beam, block, thick beam, and Pantheon-inspired examples. See the Examples page for a guided list.
| Feature | ForcePAD | Typical commercial FEA workflow |
|---|---|---|
| Open source | Yes | Usually no |
| Sketch-based modelling | Yes | Usually no |
| Real-time interaction | Yes | Often limited |
| Educational finite element focus | Strong | Varies |
| Lightweight desktop workflow | Yes | Often heavier |
| Topology optimisation experiments | Yes | Varies by product/license |
ForcePAD uses CMake and vcpkg. The primary maintained target is qtforcepad.
cmake -B build-debug
cmake --build build-debug --config DebugThe executable is written to bin/Debug/qtforcepad.exe on Windows. More detailed build notes are available in the developer documentation.
ForcePAD was developed at the Division of Structural Mechanics, Lund University, and has been used in structural mechanics education and research. If ForcePAD helps your teaching, research, or publications, see Cite ForcePAD or the repository CITATION.cff.
- Report bugs and request features in GitHub Issues.
- Read CONTRIBUTING.md before opening a pull request.
- Use the Roadmap to see planned project directions.
- GitHub Discussions is a good fit for teaching questions, example requests, and general usage support once enabled in the repository settings.