Creating your own 3D models: programs for getting started
are explained briefly when you hover over or tap them.
At some point you will no longer find a ready-made model that fits exactly: the bracket is two millimetres too narrow, the spare part does not exist. Then it is worth designing it yourself. For simple parts, an afternoon of learning is enough, and most programs are free for private use.
Two kinds of programs
CAD programs work with exact dimensions. You draw a sketch, specify lengths and extrude a solid from it. Ideal for brackets, enclosures, spare parts and anything that has to fit somewhere. Most are parametric: every step is saved, and if you change a dimension later, the model adapts.
Mesh and sculpting programs shape surfaces freely like clay. Good for figures, animals and organic shapes, unsuitable for precise fits.
What files the two approaches produce is explained in the article on file formats.
The programs at a glance
Tinkercad
Free from Autodesk, runs in the browser. You assemble basic shapes such as cubes, cylinders and spheres and subtract holes from them. You will understand how it works within an hour. For simple brackets, signs and name tags, that is perfectly sufficient. You quickly hit limits with curves, chamfers and more complex parts.
Fusion
Autodesk’s formerly Fusion 360 is a full parametric CAD program for Windows and macOS. The licence for private use is free but comes with conditions: non-commercial projects only, less than US$1,000 revenue a year, and at most 10 simultaneously editable documents. The licence runs for three years and then has to be renewed. Export as STL, 3MF and STEP is possible. If you earn money with your designs, you need a paid subscription.
Onshape
Parametric CAD in the browser, also on tablet and smartphone. The Free plan costs nothing but has two catches: all documents are public and visible to others, and commercial use is not allowed. The Standard plan costs about US$1,500 a year. For hobby projects that you would share anyway, the Free plan is a good option, especially since nothing needs to be installed.
FreeCAD
Free and open source for Windows, macOS and Linux, with no restrictions on use, including commercial. With version 1.0 (2024) and 1.1 (March 2026), the program has become much more stable and beginner-friendly, for example through a built-in assembly function. Even so, it takes more getting used to than Fusion or Onshape. If you want to be independent of subscription models in the long run, this is where to invest your learning time.
Blender
Free and open source, actually intended for animation and graphics. Strong for figures, sculptures and organic shapes. For dimensionally accurate technical parts, Blender is awkward. Pay attention to the units when exporting, otherwise the model arrives in the slicer at the wrong size.
Shapr3D
A CAD program for iPad, Mac and Windows that works well with a pen or touch. The free Basic plan allows only two projects and exports STL and 3MF in basic resolution. The Pro plan costs about US$300 a year plus VAT.
The programs compared
| Program | Cost (private) | Platform | Difficulty | Good for |
|---|---|---|---|---|
| Tinkercad | free | Browser | very easy | first steps, simple parts |
| Fusion | free with restrictions, non-commercial only | Windows, macOS | medium | technical parts, assemblies |
| Onshape | Free plan is free, documents public, non-commercial | Browser, tablet | medium | technical parts, no installation |
| FreeCAD | free, also commercial | Windows, macOS, Linux | medium to hard | technical parts, open source |
| Blender | free | Windows, macOS, Linux | hard | figures, organic shapes |
| Shapr3D | Basic free (2 projects), Pro about US$300 a year | iPad, Mac, Windows | easy to medium | CAD with pen and touch |
Licence terms and prices change. Before you start, check the provider’s current terms, especially if you want to sell.
Without your own CAD: customisers and AI
Customisable models: On Thingiverse and MakerWorld there are parametric models where you enter dimensions, text or the number of compartments in a form. The platform generates the matching file from it. For boxes, signs, cable holders and the like, this is often quicker than designing it yourself.
Image-to-3D with AI: Some services generate a 3D model from a photo or text. For decorative figures this can work. The results, however, are meshes without exact dimensions, often with errors in the geometry, and are not suitable for parts that need a fit. Also note that some platforms label or reject AI-generated models.
Designing for 3D printing
A model that looks good on screen is not automatically easy to print. These values help you design correctly from the start:
- Overhangs up to about 45 degrees are manageable for almost any printer without supports. Shallower overhangs need support. When and how is covered under Supports.
- Chamfers instead of curves on the underside: A 45-degree chamfer prints cleanly, while a curve at the bottom creates a shallow overhang.
- Tolerances for fits: For parts that are pushed into each other, allow 0.2 to 0.3 mm of clearance per side. For moving parts such as hinges, more like 0.3 mm or more. For important fits, print a small test piece first.
- Wall thickness: With a 0.4 mm nozzle, a line is about 0.45 mm wide. Plan walls as a multiple of that, for example 0.9 or 1.8 mm. The slicer cannot print walls thinner than one line width. More on this under Walls and top layers.
- Keep bridges short: Horizontal spans without support usually work over a few centimetres, and longer becomes risky.
- Think about print orientation: FDM parts are weakest along the layers. Orient parts that take force so that the load does not pull the layers apart.
- Design holes for threaded inserts according to the insert manufacturer’s specification, see Threaded inserts.
At the end, export as STL or 3MF for the slicer and keep the original file or a STEP file so that you can still change something later.
Continue with: Can I sell 3D prints? if you want to publish or sell your own models.