Whether you’re a beginner or an experienced 3D designer, you will surely get your STL file edited and repaired before 3D printing with one of the tools we’ve outlined here.

3D printing has revolutionized the manufacturing industry with the help of modern applications. Anyone with a computer and 3D printer can turn their digital design into physical objects. But you need the right 3D rendering software to personalize the 3D model (STL file). 

One of the most common file formats in 3D printing is the STL (StereoLithography) file. The STL file describes the surface geometry of a 3D object. However, even the best-designed STL files can sometimes contain errors or defects. If you have the right tool, you can easily remove the flaws before printing your 3D model. 

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The STL file errors could be holes in the surface mesh, intersections between triangles, and non-manifold edges. Fixing these issues can be time-consuming and frustrating, especially if you don’t have the proper software. That is where STL file editors come in and allow you to open, view, and edit STL files.

There are many STL file editors available, ranging from simple and free to complex and expensive. In this article, we’ll introduce you to some of the best STL file editors on the market and help you choose the one that’s right for you. 

What Is An STL File?

An STL (short for “stereolithography” ) file includes a 3D model used for 3D printing. It is a common file format in the 3D printing industry that is accepted by most 3D printers. 

An STL file represents a 3D model by approximating its surface with a series of triangles. The smaller the triangles, the more detailed and accurate the resulting 3D model will be. But a complex structure will include more triangles, and it will also increase the file size.

Numerous software is already available online for creating a perfect 3D model. Once you have created your 3D model and saved it as an STL file, you can send it to a 3D printer to create a physical model. 

The 3D printer reads the STL file and follows the instructions to craft the object layer by layer. It uses 3D printing processes such as fuse deposition modeling or selective laser sintering. 

An STL file, in short, is a digital representation of a 3D object that can be utilized to print a physical version of the object using a 3D printer.

What is an STL File Editor?

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An STL file editor is a type of software used to make modifications to an STL file and create a perfectly finished 3D model. It is commonly used in the 3D printing industry to create a physical object. 

Using an STL file editor, users can make changes to the shape and size of the model according to their preferences. Moreover, they can add or remove unwanted features such as holes or other details. 

An STL file editor can be used to make various changes to an STL file, such as:

  • Adding or deleting triangles to modify the shape of the 3D model.
  • Resizing the model 
  • Splitting the model into smaller parts 
  • Merging multiple models into one 
  • Adding or removing holes or different sections
  • Fixing any errors or defects in the file 

In addition to basic capabilities, some STL file editors may have additional features, such as converting other file formats to STL, Exporting files to other formats,  or preparing files for 3D printing. 

How To Edit An STL File?

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Once you’ve made changes or repaired your STL file using the STL file editor software, you can save the file as an STL file and use it to create a physical object using a 3D printer. Below are more detailed instructions on how to edit an STL file: 

  1. Open the STL file in a 3D modeling software or STL file editor. 
  2. Use the tools and features of the software to make the desired changes to the file. 
  3. Save the edited file as an STL file.
  4. Before 3D printing, ensure it is watertight, has a proper orientation, and includes a support structure. 
  5. Then, Send the edited STL file to a 3D printer to create a physical object. 

Remember that the specific steps and tools involved in editing an STL file will depend on the software you are using. Some software may have a more intuitive or user-friendly interface, while others offer more advanced features for more complex modifications. 

Exploring different STL editor software and learning about the available tools and features can help you find the best workflow for your needs. 

Two Major STL File Editors

As we mentioned earlier, many different STL file editors are available. But generally, STL file editors can be divided into two main categories: CAD software and Mesh editing tools.

#1. CAD software  

CAD (Computer Aided Design) software was originally intended for construction. Moreover, it offers solid modeling and precise measurements. Though CAD software is not meant to print 3D animated models, it can still be utilized to edit STL. 

#2. Mesh Editing Tools  

Mesh editing tools, on the other hand, are specifically designed for modeling objects with a 2D surface and do not include a solid fill. It is often used for mesh clearing and repair, hole filling, and vertex & edge manipulation. 

Some users may prefer the more precise measurements and solid modeling offered by CAD software. In contrast, other users may prefer specialized tools and features of mesh editing tools. The best option for you will depend on your specific needs and preferences. 

There are several STL file editing tools available for 3D modeling, customization, and printing. However, we have listed some of the top free, user-friendly, and browser-based solutions. To modify and fix your STL 3D model, check out the tools below and choose one for your next project.

Blender 

Blender is a well-known and highly-regarded 3D modeling application that offers many tools and features. With this application, users can easily create 3D printable models from scratch. Editing or repairing an existing STL file is pretty straightforward with Blender.

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However, it may have a steep learning curve due to its comprehensive set of commands. Also, it may require a powerful PC setup to display some complex models. But the best part is that it’s a free tool for working with a 3D model. Blender is available for download on Windows, macOS, and Linux.   

Editing 3D model with Blender:

  • First, download, install, and run  Blender on your PC. 
  • Next, right-click the default 3D cube and hit delete to remove it. 
  • Open Blender and import your STL file. You can do it by going to File > Import > Stl.
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  • After importing the STL file, use various tools and features to customize the 3D model.
  • You must first switch the Object to Edit Mode to edit your STL file. Now, all the edges will be visible. 
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  • Select all elements of your 3D model and press the “A” key. You can choose your preferred points, edges, or planes by drawing a box around them using the left mouse button.
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  • Now, you can add or delete triangles to modify the shape of the 3D model, resize it, split it into smaller parts, merge multiple models into one, and add or remove holes or other features.

FreeCAD 

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FreeCAD is open-source computer-aided design (CAD) software you will get for free. Both rookie and experienced 3D designers can use this software to create simple or exclusive designs. It offers features that are ideal for mechanical engineers who are creating various 3D models. 

Since FreeCAD allows parametric 3D modeling, you can easily customize your model by reviewing the previous edits. The only limitation you will face while using this software is intercepting elements structures. This software is compatible and ready to download on Windows, macOS, and Linux. 

Editing STL files with FreeCAD: 

Download, install and open FreeCAD on your PC and click File > New.

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  • Now, Click File > Import, and select your STL file. The STL file will be visible within the FreeCAD software interface. 
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  • You can set your workbench by clicking the dropdown menu and selecting Part.
  • Select your imported 3D model and click on Part > Create Sape from Mesh to get your imported model turned into small triangles. Check mark the Sew shape and keep the value of the tolerance as it is. 
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  • Now you can remove your imported mesh object. Your object currently consists of a triangle format. 
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  • Click on Task to get the Advanced Utility to construct the shape. At this point, select Solid from the shell. Select any triangle on your 3D model, click Create, and close the window
  • Finally, you will get the solid object from your imported 3D figure, which you can edit.

3D Slash

The next 3D modeling software on our list is 3D Slash, which you can use online and offline. You can craft 3D models using the classic building blocks theory that resembles Minecraft. It’s a free tool that allows browser-based 3D model editing.  

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For casual 3D model editing, it will be your best option to explore. You can avoid the complexity of any traditional STL file editor and use this tool to work with your STL file. 3D slash is compatible and ready to download on Windows, macOS, Linux, and Raspberry Pi.  

Editing STL file using 3D Slash: 

  • For browser-based operation, go to the official website of 3D slash and login into your account.
  • Click the folder Icon and then Create a new model. 
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  • Now create a new model and click the Form a 3D file option to proceed. You can either drag and drop or upload your STL file. 
  • The uploaded STL file will automatically change and transform into a pixelated object. You can edit your uploaded 3D model using the 3D slash software.
  • You will get various tools in the upper left corner of the interface. You can use these tools to edit the 3D object according to your preferences.
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SelfCAD

SelfCAD is a free tool that offers a handy user interface that makes it easier to edit STL files than other editors. You will easily get advanced features and tools to create and customize 3D models.  If you are new to 3D CAD software, this might be your best option for crafting complex 3D models. 

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Another mentionable feature of this tool is “Magic Fix”, which is best for repairing your mesh files. The tool also includes a pre-built slicer that helps you to prepare your STL file for 3D printing. So, this tool can create a much more realistic 3D model with less effort. You can download SelfCad from the official website, which is compatible with macOS and Windows. 

Editing STL files using SelfCAD:  

  • Roll over to the official website of SelfCAD and log in to your account (if you have one).
  • Now, click on New Project to start working on your project.
  • Then click Create 
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  • Next, import your STL file by clicking on File > Import. 
  • Now, you can edit your STL file according to your preferences. You can scale the object, Create holes, add & scale shapes, rotate the shape, and do much more. 
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MeshLab

Meshlab simplifies the creation, adjustment, and editing process of complicated 3D mesh files. This app includes all the necessary features to customize, view, and repair your STL and other file types.

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Though you can’t create a new mesh with this app, it allows you to combine and repair your STL file effortlessly. Meshlab works on Windows (64x), macOS, and Linux, which you can download from their official website.  

Editing 3D models using MeshLab: 

  • First, you need to combine two different meshes of a 3D model. Then you can remove the unwanted parts of the mesh and repair the 3D model. 
  • Load both the 3D models you want to combine by clicking File > Import Mesh. 
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  • From the toolbar, click Show Layers and select your 3D models.  
  • Now select the models in the layer menu and click the Manipulator Tools. 
  • Transform the model by pressing T, rotating it with R, and scaling it with S.
  • You can move or rotate the object in a different direction. Rotate the object by pressing Escape. When you are satisfied with the placement, press Escape again and transform.
  • Confirm the placement by hitting Enter
  • When all the parts are adequately placed, right-click in your combined mesh and click Flatten Visible Layer. Then tick mark the first three options and click Apply. 

SketchUp 

SketchUp, previously known as Google SketchUp, is now owned by Trimble Buildings. The free version of this 3D modeling software is named SketchUp make.

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It is the most renowned tool you can utilize to start your CAD design. Sketchup is a Windows-compatible program you can download or use in your browser.

SketchUp is packed with various features to craft a 3D model easily. Though you cannot build a solid object directly or convert the triangles of your STL file into squares. However, you can include add-ons to make this tool more effective for 3D model customization and printing.

Editing STL File Using SketchUp: 

  • First, go to SketchUp for free, click Start Modeling, and log in using your Google account. 
  • Then click Create New.
  • Now Right Click on the pre-built model and Delete it. 
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  • Click the Bread Crumb button in the top left corner, and click Import. Now import your STL file.
  • Now you can Edit your STL file using the tools available on the right and left side of the user interface. 
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SkulptGL 

SkulptGL is a browser-based application that is excellent for getting started with 3D modeling. You can take your initial steps toward the STL file modification tool, which is free to use. 

SkulptGL does not include complex features and only contains essential tools for editing and repairing STL files. As a beginner, you can begin your project with this tool over other options for your future 3D sculpting project.

Editing STL files using SuptGL: 

  • Go to the SkulptGL website and click Scene > Clear Scene to delete the default 3D object.
  • Click File (Import/Export) > Add (obj, SGL, PLY, STL)
  • Use the tools and options located on the right side to edit your STL file.

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  • You can enable the Symmetry button to minimize your workload. 
  • To add small details to your model, you can increase the resolution. You can either select Topology > Multiresolution > Subdivide or Remesh the model by choosing the resolution at Topology > Voxel Remeshing > Resolution and clicking Remesh.
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Final Words

Since most 3D printers support STL files, it’s an essential format for the 3D printing industry. Editing and repairing the STL file will not be straightforward if you use a complex tool. Only the right tool will enable you to get a flawlessly built 3d-printed model from an STL file. 

We’ve recommended some of the best STL file editor tools in this article to assist you in preparing STL files for 3D printing. These tools are user-friendly as well as free of cost. So, let’s get started with your next 3D printing project.

You may also explore the best 3D rendering software for professionals.