FreeCAD

Yes, without qualification. It is LGPLv2+ with no paid tier, no watermark, no commercial restriction and no API limit. The only attempt to build a business on top of it, a venture-backed startup called Ondsel founded by core contributors, closed in November 2024 after finding that a paid wrapper had no market among users who chose the software precisely to avoid subscriptions. Ondsel donated its remaining 40,000 EUR to the FreeCAD Project Association, which now issues grants to fold those interface improvements into the free version.

It is mitigated, not cured, and the distinction matters in practice. Version 1.0 added an algorithm that tracks how faces and edges change through the modelling history, but the official documentation still warns that edge numbers are not completely stable, and users continued reporting broken attachments through 2026. The mitigation is best understood as a safety net that reports a broken reference clearly instead of silently producing wrong geometry. The standard defence is unchanged: attach sketches to origin planes and datum planes rather than to generated faces.

It can produce a solid, and it is the only free tool that completes the job, but the result is only editable if you run the final refinement step. Part ShapeFromMesh gives every triangle its own flat face, Convert to solid closes the shell, and Refine Shape merges coplanar facets back into continuous faces. That last command is what separates a usable model from a faceted one. It also fails most often on dense scan data, where the algorithm behind it is prone to geometric exceptions.

The split is philosophical before it is technical. Fusion is cloud-anchored and subscription-based, so access to your own files depends on an account in good standing; FreeCAD is local and permanent. Fusion is ahead on interface polish and on automated CAM toolpath generation, though the CAM library rebuilt in 1.1 narrows that. FreeCAD is ahead on scriptability and on running with no network at all. For mesh to solid work specifically, Fusion's better algorithms sit behind a paid subscription, which changes the free-versus-free comparison considerably.

No licence cost exists, so the real budget line is time. Expect a longer ramp-up than any commercial alternative, occasional instability on complex models, and some internal Python work to reproduce automation that commercial suites ship with. Reviews reflect the pattern: SourceForge shows an overall 4.5 but rates ease of use at 3 out of 5, and its 124 ratings split sharply into 105 five-star and 12 one-star with almost nothing in between.

No, and this is widely misreported. FreeCAD's own announcement for 1.1.3, dated 25 July 2026, says it fixes repeated version update warnings when saving files and states plainly that no security risks or crashes are involved. The security work shipped two days earlier in 1.1.2, where roughly 12 percent of the backported patches were security fixes and 32 percent addressed BIM, Arch and the core.

STEP is the one that matters, and support extends to AP242, the standard used in aerospace and automotive that carries product manufacturing information and assembly structure alongside geometry. IGES and BREP are also supported for older workflows, IFC for BIM, and DXF for 2D. DWG works through an external converter that has to be installed separately rather than being built in.