How to prepare a 3D model for printing (STL, STEP, 3MF)
A practical guide to preparing a 3D model for custom printing: file formats, tolerances, wall thickness and the most common mistakes to avoid.
A quality print starts with a good model. Whether you create the model yourself or receive it from a supplier, it pays to know a few basic rules. You'll save both time and money.
Which file formats to send
- STL: the most widespread format for 3D printing (a mesh of triangles).
- STEP / STP: a parametric format, ideal for precise technical parts.
- 3MF: a more modern format that also carries colours and other information.
If you have a choice, STEP is best for technical parts because it preserves the exact geometry.
What to keep in mind during design
- Wall thickness: walls that are too thin may not print. Stick to at least 1–2 mm depending on the technology.
- Tolerances: for parts that fit together, allow for a small clearance.
- Overhangs: with FDM they need supports, so account for them in the design.
- Orientation: it affects both strength and surface quality.
The most common mistakes
- An unclosed ("leaky") mesh: the model isn't watertight.
- Flipped face normals.
- Details that are too small for the technology to hold.
We can fix most of these problems for you. If you don't have a model at all, we'll design it from a drawing, a photo or a sample. See our 3D modeling service.
Not sure whether your model is ready? Send it to us and we'll check it before quoting.
This article was prepared by the 3D tlač na zákazku editorial team with the help of AI tools. Every text goes through expert and editorial review, the figures are verified against the sources cited in the article, and we hold editorial responsibility for the published content. If you spot an inaccuracy, let us know.