Free SolidWorks Alternatives — Parametric 3D Modelling Without a Licence

SolidWorks is the standard for parametric mechanical modelling, and its licence is expensive. Before looking for a free alternative it is worth understanding that "free" in 3D CAD covers three very different things: completely free, including commercial work for clients; free with conditions — home use only, or public files; and a student licence, which may not be used on paid projects. An engineer working for clients needs only the first category. This article sorts them out.

Completely free — commercial work included

1. FreeCAD

The only complete open-source alternative. Sketch-based parametric modelling with constraints, a feature tree, built-in assemblies since version 1.0, and dimensioned production drawings. Beyond that it has workbenches basic SolidWorks lacks: finite element analysis with CalculiX, CAM for milling toolpaths, and BIM. It reads and writes STEP and IGES, so you can exchange files with any commercial package.

What's missing: a less polished interface, and changing an early sketch in the tree can still break features built on it. Version 1.0 improved this a great deal, but plan the tree carefully.

2. SolveSpace

A small, fast parametric modeller with a particularly strong constraint solver. It excels at simple mechanical parts and mechanisms — you can check a mechanism's motion directly from its constraints. The program is tiny and starts instantly.

What's missing: no parametric fillets or chamfers, and it is not suited to large assemblies.

FreeCAD

FreeCAD Project

Open-source parametric 3D modeller with workbenches for solid modelling, FEM, drafting and BIM.

Civil EngineeringMechanical EngineeringCompletely FreeOpen SourceLinuxmacOSWindowsCAD & Drafting

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SolveSpace

SolveSpace Project

Lightweight parametric modeller with a strong constraint solver, for mechanical parts and mechanisms.

Mechanical EngineeringCompletely FreeOpen SourceLinuxmacOSWindowsCAD & Drafting

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Modelling in code

A different approach: you write the model as a program, and every dimension is a variable. Changing one parameter produces a whole family of parts, and the file goes into version control like any code.

CadQuery writes models in Python on top of the OpenCASCADE geometry kernel and exports true STEP — exact geometry you can send to production. OpenSCAD is the veteran and the most popular, very common in 3D printing. JSCAD works in JavaScript directly in the browser.

Note: OpenSCAD and JSCAD export a triangle mesh (STL), not exact geometry. That is enough for printing, but not for a production drawing or precise machining. For that you need CadQuery or FreeCAD.

CadQuery

CadQuery Project

Parametric CAD scripted in Python, on a proper solid-modelling kernel.

Mechanical EngineeringCompletely FreeOpen SourceLinuxmacOSWindowsCAD & Drafting

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OpenSCAD

OpenSCAD

Code-based 3D modelling where every dimension is a real parameter. Popular in 3D printing.

Mechanical EngineeringCompletely FreeOpen SourceLinuxmacOSWindowsCAD & Drafting

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JSCAD

JSCAD Project

Build 3D models by writing code, in the browser or from the command line.

Mechanical EngineeringCompletely FreeOpen SourceRuns in the BrowserCAD & Drafting

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Free with conditions — read before installing

Onshape — the free plan

Full parametric CAD running in the browser, with version control and collaboration built in — technically one of the best alternatives to SolidWorks. But on the free plan every document is public and visible to anyone. For a client project that is simply not possible.

Autodesk Fusion — personal licence

Strong cloud CAD and CAM, but the personal licence is for non-commercial home projects only, with limited capabilities compared with the paid version. Excellent for hobby and learning. For paid work — no.

Onshape (free plan)

PTC

Parametric CAD in the browser with version control. On the free plan every document is public.

Mechanical EngineeringLimited Free VersionRuns in the BrowserCAD & Drafting

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Autodesk Fusion (personal use licence)

Autodesk

Cloud CAD/CAM. Free personal licence for non-commercial home projects, with reduced capability.

Mechanical EngineeringFree for Eligible Users OnlymacOSWindowsCAD & DraftingSimulation & FEA

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Adjacent tools

BRL-CAD is a CSG solid modelling system aimed at analysis — for example penetration and line-of-sight calculations — not at production drawing. Blender is excellent for visualisation and presentations, but it is not engineering CAD: it has no exact dimensions and no parametric history.

BRL-CAD

BRL-CAD Project

CSG solid modelling with built-in ray tracing, aimed at analysis rather than drafting.

Civil EngineeringMechanical EngineeringCompletely FreeOpen SourceLinuxmacOSWindowsCAD & Drafting

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Blender

Blender Foundation

Full 3D suite — modelling, visualisation and presentation-quality rendering, with Python scripting.

ArchitectureMechanical EngineeringCompletely FreeOpen SourceLinuxmacOSWindows3D & Visualisation

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The real problem: SolidWorks files

No free program reliably opens native SolidWorks files (SLDPRT and SLDASM). If a client or supplier sends you such files, ask for STEP. That is the format that moves between all programs without losing geometry — but the parametric history, meaning the ability to edit the features, does not come across.

So which one

Professional work for clients: FreeCAD. A quick mechanical part or mechanism: SolveSpace. A parametric family of parts: CadQuery. 3D printing: OpenSCAD. Hobby or learning, and public files are fine: Onshape or Fusion.

Further reading

• 10 Free AutoCAD Alternatives — and When Each One Fits
• Free FEA Software — Real Alternatives to ANSYS Mechanical and Abaqus
• Free Revit Alternatives and Open BIM — What Is Actually Possible, and What Is Not