How to create STL files for 3D printing
To create an STL file for 3D printing, you need to model the object in a CAD or 3D modeling program and then export it in the correct format. STL (Standard Tessellation Language) describes the surface of the object as a network of triangles and is used by almost all 3D printers and slicer programs. Below we go through the process in detail.
Model the object in the right program
First you need to create a 3D model. Here are some common programs depending on the application:
| Program | Suitable for | Type of modeling |
| Fusion 360 | Mechanical parts, technology | Parametric CAD |
| Blender | Organic shapes, sculptures | Polygon modeling |
| TinkerCAD | Simple models, beginners | Web-based, block-based |
| SolidWorks | Engineering applications | Advanced CAD |
| SketchUp | Architecture, concept | Surface modeling |
Check the model for 3D printing
Before exporting, you should check the following:
- Is the model waterproof? All surfaces must be contiguous and fully enclosed.
- Does the model have the right scale and dimensions? Use millimeters as the unit.
- Is the model free of internal geometry and duplicates? Remove superfluous parts.
Most programs have tools to check and fix errors:
- Blender: 3D Print Toolbox
- Fusion 360: Make > 3D Print > Preview Mesh
- Cura/PrusaSlicer: Often shows problems when importing
Export as STL
Here's how to do it in different programs:
Blender
File > Export > STL
Make sure ”Selection Only” is checked if you only want to export the selected item.
Fusion 360
Make > 3D Print > Export STL
Select the object and set the resolution (usually ”High” for best results).
TinkerCAD
Export > .STL
Simple and direct, perfect for beginners.
Verify the STL file
After export, it is good to check the STL file in a slicer program (e.g. Cura, PrusaSlicer) or an STL checking tool such as Meshmixer or Netfabb. This will help you detect any problems before sending the file to the 3D printer.
Tips for effective exporting
- Triangle size: STL files use triangles to define surfaces - more triangles mean more detail but a larger file size.
- Simplicity: Avoid unnecessarily complicated models - they can make printing difficult.
- File name: Use clear names that reflect the content and version of the model.
At RPS, we offer an online platform where you can upload STL files directly and get an automated price estimate. It's a quick way to get insights on material cost, printing time and best material choice for your model. We can also help you optimize STL files for better printing results.