How to Create STL Files for 3D Printing

by Mike Brooks | Last Updated: June 25, 2022

STL files are formed through Computer-Aided Modeling (CAM) programs. This modeling software enables one to create desirable 3D models.

How to Create STL Files for 3D Printing

After completing 3D models, you can “slice” STL files using Cura or the file slicer. Understanding the entire process enables you to carry it out efficiently and with clarity.

This article provides you with a detailed step-by-step process on how to create STL files for 3D printing in the easiest way.

Also, I’ll describe how to convert an image into an STL file, the commonly used software used for creating 3D printing STL files by beginners, plus how to create and edit STL files through that software.

Also, we’ll answer your burning questions about 3D printing STL file creation.

What’s an STL File?

STL is an acronym standing for Standard Tessellation Language (STL). It’s a commonly used file format for preparing STL files used for 3D printing.

It’s also called stereolithography, and 3D systems design STL files for CAD software.

STL file format is supported by other software, whether it’s mesh editing tools or CAD software.

You can use this file format for rapid prototyping, computer-assisted manufacturing, and 3D printing. STL format signifies model surfaces containing small triangles. If a model has a complex structure, then it holds more triangles.

Therefore, an STL format is a standard file formatting used by most additive manufacturers as a triangulated 3D CAD model representation.

Sometimes, you’ll be required to edit the STL format. But don’t worry because we’ll tell you more about STL Format editing too.

How to Create STL Files for 3D Printing?

You can access the step-by-step instructions below on converting CAD programs to STL files from 3D printing forums and each software’s website.

We’ve simplified them for you. If you don’t find the specific software you require, please be sure to contact your software support for instructions or info about an STL.

Creating an STL file is done in five steps:

Let’s look into each one at a time.

Choose Your Preferred CAD Program and Open It

There are various CAD programs to create your STL file; some suit 3d Printing beginners more than others, while other software is best for 3D model engineers and others for 3D model artists.

For instance, if you’re a starter, consider TinkerCad or Sketchup, while 3D model engineers can go for Autodesk Inventor, CATIAI, Ron CAD, Rhinoceros, PTC Creo Parametric, Solid Edge, SolidWorks, or NX. On the other hand, 3D model Artists can choose Blender, ZBrush, or Maya. Whichever software suits you, please select it.

Some advanced programs require payments, but the best beginner software like TinkerCad, Sketchup FreeCAD, and Onshape doesn’t require purchasing because they are free.

Plus, since beginners don’t need a complicated user interface TinkerCad, for instance, was made with you in mind because you don’t need to install big programming files to start. Instead, you just need an account and an understanding of how to use it.

Create 3D Models Using Your Software’s Tools

To create 3D models for additive manufacturing, first, download a suitable tool. Ensure you understand their terms and accept their cookies.

Cookies enable you to enjoy the user interface, and they provide enhanced functionality. Cookies collect personally identifiable information to enhance your experience.

Then prepare the workspace and view the basic tools that function correctly without showing an error message. Some devices like meshwork editing tools have no filling, just a shell making them ideal for editing.

Afterward, sketch axes and draw basic 2d models using your chosen tool. Please find here the detailed guide on how to make 3D models.

Save and Export Your Design to the Computer

I’ll use TinkerCad because it’s not only suitable for modeling beginners but also exports the models to your computer. It’s an ideal program, right?

You can easily export your STL file to your computer without downloading them because it has an autosave feature that ensures you don’t lose your work.

It identifies your browser and internet device through cookies without intruding on your privacy as they don’t store directly personal information.

Exporting CAD files is easy. Press “Export” on your page, After clicking that button, a box pops up containing several options. Most pages bring STL files with names like Standard Tessellation Language, Stereolithography, or Standard Triangle Language.

Use the one that presents to you. You can also use Blender.

Before Exporting Note the Following

Before exporting your CAD file, ensure your model is uniform. You can do that by ensuring your vertices are connected. Checking file uniformity requires the following essential steps.

First, enter the Edit mode and select your file. Then long press “L” across the mesh. Upon doing that, the areas that won’t highlight are floating. Ensure you connect the vertices for printing on your part.

After confirming your object’s uniformity, check your mesh part for holes, enter edit mode, deselect the vertices, and click Non-manifold from your drop-down menu.

Afterward, change your object’s dimensions metrics or millimeters and adjust your scale. After these steps, you can comfortably export your file. You can apply modifiers as you export or before exporting.

Pick File > Export as .STL (* .stl)

Choosing a Slicer Software

Most 3D model engineers, artists, or beginners are either well-versed or have crossed paths with Cura by Ultimaker. It’s a popular cross-platform software for slicing CAD files to prepare STL files for 3D printing.

Cura works adequately and does the job just fine. Therefore, although they’re more slicing applications, we’ll focus on this one because it’s beginner-friendly, and you won’t need much time to understand it.

Some other slicer programs have enhanced functionality specifically dedicated to printers, but they essentially perform the same task as Cura.

Slicing Your File Into a G-code File

“File slicing” is a widely used term in 3D printing. It means you prepare your CAD file and transform it into a G-code file usable by your 3D printer. G-code command series directs your printer in fan speed, movement, and temperatures.

After slicing your file, you can preview the model as a 3D object. Here, you can view every print layer from the bottom, observing how the object’s head goes while printing.

To follow such, look over your settings and click the slice button located in your software’s bottom right corner.

The good news is, Cura has default profiles with a built-in slicer tool, and you don’t have to undergo the hustle of setting up your g-code interface to have desired settings.

Cura software works by itself, although it takes some time to acquire great prints. Hence, you can choose to customize settings to achieve great images.

How Do I Convert an Image Into an STL?

Converting an image into an STL file requires you first to convert the image into grayscale. Tools like IMAGEtoSTL examine the small details of your print or JPG file based on the luminosity of every pixel. Then it creates the corresponding 3D pixel.

Its luminosity determines the pixel’s height; black pixels have a resistant size which does not get included in the final 3D model.

On the other hand, white pixels generate adequate height, which you can specify once you upload your image.

The STL form may be printed or get further processing by loading it into new models of 3D mesh editing like Blender.

The Blender comes in handy for video game developers to create 3D models from images for games or other apps.

How to Edit STL Files

Editing an STL file is done through two different types of modeling software; CAD software and mesh editing tools. CAD (Computer-Aided Design) Software constructs provide exact solid modeling and measurements.

Such devices aren’t suitable for 3D printing and don’t show full strength while editing STL files. Such tools include TinkerCad, Blender, and FreeCAD.

Meshwork editing tools make animations, modeling, and 2D surface objects. They have no fillings, only a shell. Therefore, this feature enables them to make thin walls when not solidified.

Those walls are unsuitable for three-dimension printing. Meshwork editing tools are ideal for STL file editing. These tools are like Meshlab and Meshmixer.

How Do I Create an STL File in Blender?

Blender software mainly imports and exports STL from and to your computer. While exporting, first save(File ‣ Save) the existing work, then select export (File ‣ Export ‣ STL). While importing the just-exported STL, follow: (File ‣ Import ‣ STL).

Please note: as you open another person’s STL, Blender doesn’t “know” ahead of the STL files initially stored.

The software stored some units in STL files, Blender assumes meters, and you may lose them. Therefore be on the seaside by ensuring you save your units.

Which Software Is Used for STL?

1. TinkerCad

We can use TinkerCad as an example because it’s easy to use. While preparing shapes and blocks, you can gradually create complex models that will impress you.

It’s easier to follow this simplified tutorial here on how to use TinkerCad for 3D models. TinkerCad Prints simple geometrical models, and it’s ideal for 3D printing.

2. SketchUp

On the other hand, it doesn’t directly offer STL creation, but you must undergo several routes to create an STL file; you can download its STL format extension here. Please note: this source frequently updates as it’s open-source.

Also, SketchUp isn’t suitable for model production as that isn’t one of its inherently built features. Hence, you should check your Sketchup file for additional features once you export it from the Sketchup user interface. Which helps eliminate surface flaws present on your file.

SketchUp isn’t suitable for 3D printing because it doesn’t export correctly. However, instead of producing physical models using this program, you can use it for sketching early designs.


CATIA V5 can transform CATPart files into STL files but can’t create STL files from geometrical representatives or CATproducts. Hence, you should save source files as CATParts, including those held in neutral formats like IGES or STEP.

When your source design is imported as a CATProduct, it means you had saved it as an assembly, and converting it to an STL file requires you to convert it into a multi-bodied part.

The source design will be imported as a CATProduct to CATIA if it was saved as an assembly. You will then need to convert it to a multi-bodied part before creating an STL file.

There are two points to have in mind here. One, some components of the combined elements may fail to align correctly due to the initial design of your assembly. Here, you can align them back by selecting “Insert Menu” and then “Constraints Feature”.

Second, please have higher settings for the accuracy ratio of your model’s curves. Why? Because higher settings produce smoother surfaces for complex geometries, especially the ones with small radii.

4. MeshLab

Meshlab is an open-source meshwork editor that will edit all STL files. It’s free, and you can use it for professional uses because it contains numerous point clouds and mesh processing functions.

This tool manages large files, which avails many immense file management possibilities.

Plus, Meshlab contains many processing tools, including mesh analytics, remeshing, automatic smoothing, visual inspection, and cleaning errors, making it a mighty STL file editor.

This capability means that by merging existing models, you can create new models.

5. MeshMixer

Meshmixer is another free editing tool that you can directly download from Autodesk’s site. This software has an easy-to-use user interface, especially while editing STL files, resizing 3D objects, or changing some aspects.

The programmers ensured it covers all issues you’ll likely encounter with the file.

Final Thought

After those simple steps, you’ve finally created your 3D printer STL model. After slicing a CAD file, get your USB drive or micro SD card, plug it into your personal computer, and save it as your removable object, and voila!

With these simple steps, you can start creating your STL files for 3D printing.

Michael Brooks is the founder of He sees a very bright future for 3D printing that's why his mission is to try and make this easy for everyone. Discover your hidden talent and creativity. You can follow here: Facebook, Twitter & Pinterest.