Free CAD Software for 3D Printing: Fusion, Onshape, FreeCAD and Tinkercad Compared

Written by Harry S.

Quick answer: Start with Tinkercad if you have never used CAD. Choose Onshape Free for parametric modelling in a web browser if you are happy for your designs to be public. Pick Fusion for personal use for desktop parametric CAD on non-commercial projects. Use FreeCAD if you want open-source software with no licence restrictions.

Designing your own parts is where 3D printing gets properly useful: a bracket that fits the gap you actually have, a replacement knob, an enclosure sized to your circuit board. Four well-supported programs have a free way in, but "free" means something different for each one, and the terms have changed over the years.

We checked each tool's terms on its official site in September 2026. Terms change, so confirm them before committing a big project to one platform.

The four tools at a glance

Tinkercad: the easiest place to start

Tinkercad is Autodesk's free design app. It runs in a web browser and there is a free iPad app. You build a model by dragging basic shapes onto a workplane, resizing them, and turning some of them into holes that cut away from the rest. Designs export as STL or OBJ, which any slicer will open.

There is no feature history to edit, so changing an early decision means moving shapes by hand. That is fine for name tags, spacers and simple boxes, and a good way to learn to think in three dimensions.

Onshape Free: parametric CAD in the browser

Onshape Free is a full CAD system that runs in a web browser, with iOS and Android apps. Nothing installs on your computer, and you can set up variables and use them in dimensions, so one change to a clearance updates every feature that uses it.

The catch is in the terms: the Free plan is for non-commercial use only, and every document you create on it is publicly accessible online. That suits a printer upgrade you would happily share, not a client's product. Paid plans add private storage and allow commercial use.

For printing, Onshape exports STEP, STL, 3MF and OBJ, among other formats, and the STL export lets you choose Coarse, Medium, Fine or a custom resolution.

Fusion for personal use: desktop power with limits

Autodesk Fusion (formerly Fusion 360) offers parametric, direct, freeform and surface modelling in a desktop app for Windows 11 and macOS 14 Sonoma or later. The personal use licence is free, but the conditions matter:

• It is for personal, non-commercial projects only, limited to individuals generating less than US$1,000 a year, and not for your main job, a company environment or commercial training.
• The licence runs for three years, then you reapply to confirm you still qualify.
• You can have 10 active, editable documents at a time. Other designs stay stored, and you can still open them read-only.
• Local export is limited to formats including STEP, STL, OBJ and Fusion's own F3D and F3Z files. The 3D Print command sends a model straight to your slicer.
• Simulation, generative design and cloud rendering are not included, and CAM and drawings are cut down.

FreeCAD: open source, no strings

FreeCAD is an open-source parametric modeller released under the LGPL-2.1 licence. There is no sign-up and no paywall, it works offline, and you can use it for paid work without buying a licence. It runs on Windows 10 or later, macOS 12 Monterey or later (Apple Silicon and Intel) and Linux.

FreeCAD organises its tools into workbenches for different jobs, including finite element analysis and CAM. It exports STEP, IGES, OBJ, STL, DXF and SVG, along with many other formats. It has the steepest learning curve of the four, so allow time for tutorials.

Which one should you use?

• You have never used CAD, or you are teaching kids: Tinkercad.
• Printer upgrades and household fixes you do not mind sharing: Onshape Free.
• Complex mechanical parts and assemblies for personal projects on a Windows or Mac desktop: Fusion for personal use.
• You sell prints or design for clients and have no software budget: FreeCAD. Onshape Free and Fusion for personal use both exclude commercial work.
• You want to keep designs private without paying: FreeCAD or Fusion for personal use, since Onshape Free documents are public.

Exporting your model for printing

STEP, 3MF or STL?

STEP keeps exact geometry, with true curves rather than triangles. Keep a STEP copy as your master file for sharing designs or moving them between CAD programs.

STL is the format every slicer opens, but it is only a surface made of triangles. It carries no colour, and it contains no scale information, so the units are arbitrary. If a part arrives in your slicer 25.4 times too big or too small, it was exported in inches. Export in millimetres.

3MF can carry the model together with print settings such as temperatures, the regions that use different materials, and support structures. That makes it the better choice for multicolour prints when your CAD tool exports it. Onshape does. Autodesk's personal use export list names STEP, STL and OBJ, so in Fusion you can export each body as its own STL and assemble them in the slicer.

Mesh resolution

STL and 3MF files turn curves into flat facets. If the export is too coarse, round holes print as polygons. Use the fine or high setting for parts with small holes or curved mating surfaces.

Design tolerances into the model

Printed parts never match CAD exactly, and holes usually print undersize. Put clearances into the design, not the slicer. Our tolerances and fit guide gives starting values for PLA: 0.15–0.25 mm for a slip fit, 0.25–0.35 mm for a running fit and 0.4–0.6 mm for a loose fit, with holes typically 0.1–0.2 mm undersize on a 0.4 mm nozzle.

In a parametric tool, store the clearance as a named parameter or variable so one edit updates every mating feature. Print a small test coupon of the joint before committing to a long print. For hinges and joints that print already assembled, model the gap as real geometry and follow our print in place guide. For orientation, overhangs and wall thickness, see Designing for 3D Printing: DFM Basics.

Shop the materials in this guide

• 1.75 mm PLA+ Filament - 1 KG: an easy, affordable material for prototypes and fit test coupons.
• 1.75 mm Matte PLA Filament - 1 KG: a low-sheen finish for display prototypes and design reviews.
• 1.75 mm PETG+ Filament - 1 KG: a tougher material for functional parts once the design is proven.
• Heat Set Insert Starter Kit (M2 to M5, 120 pcs): metal threads for printed parts you will assemble and take apart.
• M3 Fastener Starter Kit (140 pcs): screws and nuts for testing clearance holes and building prototypes.

Frequently asked questions

Is Fusion 360 still free?

Yes, for personal, non-commercial projects by individuals generating less than US$1,000 a year. The licence lasts three years before you reapply, with a limit of 10 active documents and fewer export formats.

Can I sell prints of parts I design in free CAD software?

Not with Onshape Free, which is for non-commercial use only, or with Fusion for personal use, which excludes commercial work. FreeCAD is open source under the LGPL-2.1 licence and has no such restriction. Whatever you use, check the current terms before you start selling.

What about Shapr3D or Plasticity?

Shapr3D's free Basic plan allows up to two projects and exports STL and 3MF at basic resolution only. Plasticity offers a 30-day trial with low-resolution OBJ and STL export and no commercial use. Neither is a long-term free option for printable parts.

Which file should I send to my slicer?

Use 3MF when your CAD program exports it, otherwise STL in millimetres at a fine resolution. Keep the native file and a STEP copy for later edits.

Related guides

• Designing for 3D Printing: DFM Basics
• Tolerances and Fit: Printing Parts That Click Together
• Print in Place Designs: Hinges, Joints, and Mechanisms
• Heat-Set Inserts for 3D Printing: Sizes, Hole Dimensions and How to Install Them