3D Learning Hub

The 7 Best Free STL Editors to Edit and Repair your STL Files


In order to 3D print or to use a 3D printing service, there is one essential thing that you need: a 3D file. You can either design one yourself or find one online. But the files you find might not always correspond exactly to your needs. It might lack some features, have too many elements in it that you don’t need, or even be damaged. Thus, you will need to edit it so it will perfectly fit your needs. You might have to do some file repairing in order to make your CAD models 3D printable.

How to do so for your STL files? That’s the question we already tried to answer a few weeks ago with this blog post. Today, we will introduce our 7 favorite free STL editors that can solve your problem and help you repair 3D models.

What is an STL file?

STL, an acronym for STereoLithography, is a file format created by 3D systems for its CAD software. It’s also supported by many other software, either CAD or mesh editing tools. It’s mainly used for 3D printing, rapid prototyping, and computer-aided manufacturing.

This format represents the surfaces of a model with small triangles. The more complex the structure is, the more triangles will be used to get the right model.

STL file format is one of the most commonly used file formats. Thus, you will find many 3D models using this file format when looking for a 3D file to 3D print. Sometimes, you will have to repair your STL files, so here are some tips to help you with this files repairing process.

Using an STL file editor

Fixing and repairing your file is not that complicated, you don’t need to be a 3D designer to do it on your own. If you want to use a modeling software to edit your STL file, you have two options:

1. You can either use a CAD software (Computer Aided Design). Initially, it’s made for construction. Thus, it provides solid modeling and exact measurements. It’s not designed for 3D printing in the first place but you can use it anyway to edit your STL files.

2. You can also use mesh editing tools. They are made for modeling and for objects represented by a 2D surface. Thus, the objects have just a shell without filling and you need to solidify your object before 3D printing it. This last part of your work is easy to do with this kind of STL file editors.

7 of the best free STL file editors


Meccanismo-Complesso-FreeCAD-logo (2)

FreeCAD is a free and open source CAD software. It uses parametric modeling and can be used by many different kinds of users, from beginners to professional 3D designers. Since it’s quite easy to use, you don’t need to be an experimented CAD designer to use it. It’s mostly used by architects and engineers because its features were built for mechanical engineers.

Since it was designed for mechanical use and not for modeling, you can’t really sculpt a model with it without difficulties. But it will be great to construct mechanical objects or to fix your STL files.


Blender STL modeling software

Blender is also a great free design software that you can use for 3D printing. It contains multiple useful features like various algorithms that smoothen and interpret a surface. With  these software tools, you can easily edit and repair your STL files. This is a great STL file editor if you need to sculpt and work on fine details of your 3D model.

But it will take you some time to get used to it because of its important amount of 3D tools and options. Another specific point: a powerful computer is needed to use Blender, especially if you have a high poly object.


Meshlab, software for 3D modeling

MeshLab is a very complete free and open source program to edit your STL files. It is especially used by professionals since they appreciate its numerous mesh and point cloud processing functions. They also enjoy the possibilities it offers in terms of management of very large files.

It has a vast set of processing tools like mesh analysis, cleaning of errors, remeshing, surface reconstruction, automatic smoothing, and visual inspection. Thus, it’s extremely powerful to edit your STL files. You can’t create an STL file from scratch with it, but you can create new models by merging some existing ones.

MeshMixer is a free mesh editing software. You can download it


Meshmixer 3D printing modeling software

MeshMixer is a free mesh editing software. You can download it directly from Autodesk’s website. It’s very easy to use if you want to edit STL files, especially if you just wish to resize your 3D object or to change some aspects of it. It takes into account all the different issues that you may face with your file. These software tools will allow you to get a repaired file, ready for the additive manufacturing process.

Moreover, it also has a built-in slicer tool. Thus, you can directly send your file from MeshMixer to a 3D printer.


Sketchup logo

SketchUp, which used to be called Google SketchUp, is a 3D modeling software that now belongs to the architectural company Trimble Buildings. It’s available in its commercial version as SketchUp Pro and in its free version as SketchUp Make. This is one of the most used software to start CAD design.

One of its major advantages is that it’s easy to use and that it offers all the tools to create a 3D model. But some key features of an STL file editor are missing. For example, you can’t create directly a solid object, or you can’t transform the triangle mesh of your STL file in squares which are easier to edit.


SculptGL for 3D printing

SculptGL is a free 3D sculpting tool. It’s a great software to get started with 3D sculpting and to make your first step in STL files editing with this kind of tool.

Unlike professionals sculpting software like ZBrush, it only includes the basic tools you need to edit and repair your STL files. As a result, for further use of 3D sculpting, we advise you to switch software.



3DSlash is an easy to use and free 3D modeling software. It allows you to create 3D models easily with a building-block concept inspired by Minecraft. You can download it for free and even access the free 3D editor directly from your browser.

Since it’s a quite simplified software, it will be great for hobbyists but not really for professionals. Thanks to it, hobbyists can edit their STL files without having to learn how to master a 3D modeling software.

Discover Sculpteo’s online editing and repairing tools for your STL files

Great news: you actually don’t always need to use an STL file editor to edit and repair your STL files! Indeed, if you don’t know how to use 3D tools and don’t want to use a design software to fix your STL files, we will repair your CAD models for you. Most of the tools you need are available online, you can fix your files directly on Sculpteo’s website when you upload your STL file.

We provide you with 3 different types of tools. Discover them now by uploading your STL file.

Optimization tools

These tools help you optimizing your STL file for 3D printing. You can, for instance, hollow it, to waste less material and to get a lighter object. You can also use our batch control, and our orientation tool.

Learn more about our optimization tools in this blog post.

Repairing tools

Not all 3D files are printable. How can you repair them? Our online repairing tools help you to do so. Multiple algorithms directly analyze and repair your STL file so that you can 3D print it!

Learn more about our repairing tools in this blog post.

Reviewing tools

Last but not least, you can directly review your 3D model on our website before 3D printing it. We offer solidity checkthickeningcutaway view and 3D print dossier. You will then be sure that your STL file is correct.

We hope that you found the perfect STL editor to repair you 3D model. Now that you have repaired models that are totally 3D printable, you can upload your files directly on our online 3D printing service. Our 3D printers will take care of your CAD models and you’ll get your 3D printed objects in just a few days!

Learn more about our reviewing tools in this blog post.

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