STL Viewers: Free and Open Source Programs to Download

Review your STL files before sending them to a 3D printer

STL files are the most common file format for 3D printers. When working with 3D printers, it's important to view your STL file and make sure it is correct before printing it. Free STL viewers let you examine a model without using processor-heavy CAD programs. Review your work, or someone else's work, and make sure it's perfectly edited and scaled.

We evaluated free and open-source STL viewers and rated these viewers according to ease of use and functionality. Here are our picks for the 13 best free STL viewers.

If your STL files need editing or repairing, you'll need an STL editor. Some of these programs offer STL viewing and editing features, while others allow only viewing.

01
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Best for Ease of Use: STLView

STLView free STL viewing software
What We Like
  • The device's G-sensor views a model from different perspectives.

  • Optimized for large models and fast graphics.

  • Load multiple models at the same time.

What We Don't Like
  • No Mac or iOS version available.

  • No edit or repair functions.

STLView, from ModuleWorks, is a free, basic STL viewer available for multiple platforms. It supports both ASCII and binary STL formats and loads more than one model at once. It works well with large models and is optimized for fast graphics. Use STLView to display your model from different perspectives, zoom in and out, and change colors. This is a free tool that's handy and easy to use.

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02
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Best for Communication: MiniMagics

MiniMagics free STL file viewer
What We Like
  • Make text annotations to communicate with others.

  • A friendly user interface.

  • Create a printout of all parts of a project.

What We Don't Like
  • No Mac, Linux, Android, or iOS support.

MiniMagics, from Materialise, is a free STL viewer that works with Windows 10, 8, and 7. Use this tool to view STL files, perform measurements, and communicate with others on a project team, such as a manager or client. You can also view parts and rotate, pan or zoom, add text annotations, and verify printability.

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03
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Best Multiple-Function Tool: Meshmixer

Meshmixer STL file viewer and editor for 3D printing
What We Like
  • Edit and repair STL files.

  • Useful 3D design tools.

  • Simple, friendly user interface.

  • Support Generator tool helps with 3D printing.

What We Don't Like
  • You'll need a powerful system to support all its features.

Meshmixer is more than an STL viewer. You can also use it to edit and repair STL files as well as create 3D designs. With a vast range of 3D modeling functions, Meshmixer is a powerful tool, focusing on 3D printing. It's a great choice if you need to clean up a 3D scan, design a new object, automatically repair STL files, and more.

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04
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Best Basic Viewer: SolidView/Lite

SolidView Lite STL file viewer
What We Like
  • View and save images in a variety of formats.

  • Share files with others to view.

What We Don't Like
  • Available only for Windows.

  • Must upgrade to paid versions for additional functionality.

If you're looking for a simple, basic STL viewer, SolidView/Lite allows you to view, rotate, and print STL and SVD files. The Lite version is designed only to get your project to a basic production level. However, the company offers paid versions with high-level functionality that range from a $99 purchase to a $249.95 per month subscription.

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05
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Best Full-Featured Open-Source Tool: FreeCAD

FreeCAD design tool and STL file viewer
What We Like
  • Runs the same way on Windows, Linux, and macOS.

  • Fast rendering of 3D scenes.

  • A good user interface and can run in command-line mode.

  • Revise and edit 3D model files for printing.

What We Don't Like
  • Export function for other formats requires an add-on.

FreeCAD is a good open-source parametric modeling tool that can import and export a variety of files, including STL, DAE, OBJ, DXF, STEP, and SVG. Because it's a full-service CAD program, it's also a design tool. Design a project from the ground up as well as adjust, repair, and view designs.

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06
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Most Customizable Open-Source Tool: Wings 3D

Wings 3D open source STL file viewer and modeling tool
What We Like
  • Powerful and easy to use.

  • A range of modeling tools.

  • The customizable interface.

What We Don't Like
  • The interface requires a three-button mouse to use it effectively.

  • No support for animation.

Wings 3D is a comprehensive, open-source CAD program available in many languages. It imports and exports multiple file formats, including STL, 3DS, OBJ, SVG, and NDO. Wings 3D also offers a comprehensive set of mesh modeling and selection tools. Right-clicking in the program displays a context-sensitive menu with descriptions that appear when you hover over it.

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07
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Best for Less Powerful Computers: MeshLab

MeshLab STL file viewer and editor
What We Like
  • Edit, clean, inspect, render, and view files.

  • Prepares models for 3D printing.

  • Fast, efficient, and easy to install.

What We Don't Like
  • Can't create 3D objects from scratch.

MeshLab is an open-source STL viewer and editor created by students at the University of Pisa. It imports and exports a variety of file formats. You can clean, re-mesh, slice, measure, and paint models. It also comes with 3D-scanning tools.

MeshLab is a light and efficient tool that runs on computers without extensive processing power. Due to the ongoing nature of the project, MeshLab is constantly adding new features.

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08
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Best Barebones Open-Source STL Viewer: Viewstl

Viewstl open-source STL file viewer
What We Like
  • Small and easy to use.

  • Basic and easy-to-learn commands.

What We Don't Like
  • Need a three-button mouse for it to work best.

Viewstl is a simple and easy open-source STL viewer that shows STL files as shaded on-screen images. It also supports Ascii STL files and dynamic rotation, scaling, and panning. Viewstl has basic, easy-to-learn commands and works best with a three-button mouse.

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09
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Best Online STL Viewer: 3DViewer

3DViewer online STL file viewer
What We Like
  • Works on computers, tablets, and smartphones.

  • No download needed.

  • Personalize the viewer to match your company style.

  • Upload and share 3D models.

What We Don't Like
  • Must upgrade to a paid plan to upload multiple files or update online models.

3DViewer is a free online service. Use it to view STL files in a web browser without the need for software downloads. You can also upload 3D models, share models through the 3D Viewer, and save or share PDFs of your work.

After you create a free account, you get 5 GB of free storage. Paid versions of 3DViewer offer more storage and editing functionality.

10
of 13

Best Full-Service Modeling Program: BRL-CAD

BRL-CAD STL file viewer and modeling program
What We Like
  • Advanced modeling features.

  • Available for multiple platforms.

  • Excellent documentation and coding.

  • Continually updated.

What We Don't Like
  • It might be too complicated for a beginner.

If you're looking for a full-service modeling program, the open-source BRL-CAD system is packed with advanced features, including interactive geometry editing, high-performance ray-tracing, and more. BRL-CAD has its own interface and can convert from one file format to another. It's been an open-source project since 2004 and is used by the U.S. military to model weapons systems for vulnerability.

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11
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Best Open-Source Tool for Album Management: GLC_Player

GLC_Player STL viewing and modeling software
What We Like
  • Review loaded models while loading more models.

  • Excellent album-management features.

  • Easy navigation within models.

What We Don't Like
  • May have more functionality than you need if you're looking for a simple STL viewer.

GLC_Player is a free and open-source tool that you can use to view STL, OFF, 3DXML, COLLADA, OBJ, and 3DS files. It offers an English or French interface for Linux, Windows, and macOS. Use GLC_Player to create and manage albums, and export albums as HTML files. Use its album-management features to load several models, view thumbnails of loaded models, and switch between models. Albums files can be saved and reopened later.

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12
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Best Combination Viewer and Modeling Program: Gmsh

Gmsh open-source STL viewer and modeling software
What We Like
  • Fast and user-friendly interface.

  • Light on system resources.

  • The website offers tutorials and demos.

What We Don't Like
  • Beginners may find it too complicated, while advanced users may need more features.

With a built-in post-processor and CAD engine, Gmsh is more than a viewer. It balances somewhere between a full CAD program and a simple viewer, providing a fast, light, and user-friendly meshing tool with parametric input and advanced visualization capabilities.

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13
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Best for macOS: Pleasant3D

Pleasant3D STL viewer for Mac
What We Like
  • View STL and GCode files.

  • Simple and uncluttered interface.

What We Don't Like
  • It has only basic editing capabilities.

Pleasant3D was designed to work specifically with macOS. You can use it to view both STL and GCode files. However, it can't convert one to the other and offers only basic editing abilities. Pleasant3D functions nicely as a basic viewer without the clutter of many extras. 

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