Resources

Short, practical guides for choosing and switching to free tools, plus links to good documentation elsewhere.

Switching guides

How to move an Eagle project to KiCadKiCad imports Eagle 6.x and newer projects (XML .sch and .brd files) as a complete KiCad project, from File → Import Non-KiCad Project.
How to move an Altium Designer design to KiCadKiCad imports Altium boards (.PcbDoc) and schematics (.SchDoc) as standalone documents. Import the board first, save the project, then bring in each schematic sheet.
How to convert AutoCAD DWG drawings to DXF with LibreCADLibreCAD's command-line converters turn DWG drawings into DXF (or PDF, PNG and SVG) without opening the editor: librecad dwg2dxf -o drawing.dxf drawing.dwg.

Stars: how many people have bookmarked the project on GitHub or GitLab. It is a rough signal of popularity, not of quality, and projects hosted on SourceForge, Savannah or Bitbucket have no star count at all.
Last commit: when code was last pushed to the project's repository. A recent date means someone is actively working on it. An old date isn't always bad: some mature tools change slowly.
Licence: the terms you get the software under. Copyleft licences (GPL, AGPL, LGPL, MPL) keep the code open when it's shared; permissive licences (MIT, BSD, Apache) allow almost any use. "Free, proprietary" tools cost nothing but you can't see or change the code, and some limit commercial use.
Not open source: shown when a tool has no public source code, so there is nothing to count.

Start from the job: list the handful of things you actually do in the paid tool every week, and test those first.
Check files in and out: make sure the free tool can open your existing files and export what your colleagues, supervisor or supplier needs.
Check where it runs: Windows, macOS, Linux or the browser, and whether your organisation lets you install it.
Look at activity: the last-commit date and recent releases tell you whether bugs get fixed.
Read the licence: especially for business use: some free proprietary plans are for non-commercial use only.
Trial it on real work: run one real but low-stakes project in both tools and compare the results before switching fully.
Find the help: official documentation, forums and community chat matter more than a feature list when you get stuck.

3D parts and assemblies: export STEP files from your current CAD. STEP carries the solid geometry between almost all CAD systems.
Feature history: the design history (sketches, constraints, feature tree) does not transfer between CAD systems. Plan to rebuild the key features of parts you still edit.
2D drawings: LibreCAD and QCAD work natively with DXF. DWG support in the free versions is limited, so save DXF copies before you switch.
PCB projects: KiCad can import Eagle and Altium Designer projects. Check footprints, design rules and net classes after the import.
3D printing: export 3MF where you can: unlike STL it keeps units and multiple objects. All the slicers listed here read both.
Simulation meshes: Gmsh can write meshes in formats many solvers read, including Abaqus INP, UNV and MED. CalculiX uses an Abaqus-like input format.

FreeCAD: getting started ↗The official introduction to FreeCAD's workbenches and workflow.
FreeCAD: import and export formats ↗Which file formats FreeCAD can read and write.
KiCad documentation ↗Official manuals for schematic capture, PCB layout and importing other projects.
OpenSCAD documentation ↗Manual, cheat sheet and tutorials for code-based modelling.
Prusa knowledge base ↗Guides on slicing, materials and print troubleshooting.
Blender manual ↗The official Blender reference manual.
Gmsh reference manual ↗Meshing, geometry scripting and supported mesh formats.
Choose a License: licence list ↗Plain-English summaries of common open-source licences.

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