STL is the most common 3D model file format used in 3D printing. But STLs can develop issues like gaps, non-manifold edges, and intersecting facets that prevent successful slicing or printing. That’s where an STL file editor comes in handy for diagnosing problems and repairing models. We’ll compare the top 7 free STL editors to fix and modify your 3D prints.
What To Look For In An STL File Editor
Before diving into specific tools, here are key capabilities to look for in an STL file editor:
- Imports/exports STL files with preservation of units, scale, and orientation
- Displays and inspects models to visually identify issues
- Repairs common errors like holes, overlaps, normals, and non-manifold edges
- Allows editing of geometry with addition/deletion of facets
- Provides mesh smoothing, scaling, and cleanup functions
- Lets you customize supports, rafts, and slicing parameters if bundled with a slicer
- Offers sculpting tools to modify designs
- Has a short learning curve for basic repairs vs advanced editing
- Works cross-platform (Windows, Mac, Linux) both locally and web-based
Ideally the editor should quickly fix basic issues while also providing more advanced geometric modeling capabilities depending on your needs. Let’s explore the top free options:
1. Meshmixer – Robust Editing Plus Easy Repairs
Developed by Autodesk, Meshmixer is one of the most full-featured free STL editors available. It imports STL, OBJ, 3MF and other common 3D file formats.
The Inspector tool lets you visually inspect models and automatically highlights problem areas. Controls allow you to easily fix holes, overlaps, normals, degenerate facets, and non-manifold edges quickly.
Beyond repairs, Meshmixer includes sculpting brushes to push, smooth, flatten or otherwise modify your model geometry. The Plane Cut and Edit tools enable precise edits to cleanly add or remove facets.
For organic shapes, Meshmixer’s re-meshing algorithms can generate a new smoothed mesh from the input model. There are also tools to generate thickened shells and hollow interiors.
With a simple interface focused on streamlined workflows, you can repair and prepare prints for fabrication quickly. Meshmixer is available for Windows, Mac, and Linux.
2. Blender – Advanced Modeling And Texturing
Blender is an incredibly versatile open source 3D creation suite good for both simple STL repairs and advanced editing. It supports importing STL, 3MF, OBJ and more.
The STL Tools addon provides specialized repair features similar to Meshmixer. The Validate and Reorient operators detect issues with facets, normals, and geometry. Auto-repairs fix overlapping vertices, normals, degenerate faces, and duplicate/loose parts.
Blender also incorporates full mesh sculpting and retopology modeling capabilities for more organic edits. The texture painting tools allow you to add color or materials information to STL models as well.
With its node-based workflow and thousands of addons, Blender provides all the advanced modeling, texturing, animation, and rendering capabilities many would need. But it does have a steeper learning curve.
Blender is free and open source, available on Windows, Mac, Linux, and more. It’s ideal for making complex modifications beyond just fixing basic STL issues.
3. 3D Builder – Streamlined Slicing And Repairs
Microsoft’s 3D Builder offers a simplified STL editor experience designed for 3D printing preparation. It loads STL, OBJ, 3MF, and other CAD formats.
The 3D view highlights model issues like holes, disconnected components, flipped normals, andmanifold edges. Simply click the “Resolve” button to automatically repair many problems.
3D Builder’s Edit tools allow quick modifications like splitting, mirroring, or drilling holes in models. You can scale, smooth, and apply other filters under the Convert menu.
Once repaired, the slice tool generates print-ready gcode with configurable settings for material, quality, supports, and more.
As a free Windows 10 app, 3D Builder makes it easy to diagnose and fix basic STL issues, especially for 3D printing. But advanced editing tools are limited.
4. FreeCAD – Parametric Modeling Capabilities
FreeCAD is an open source parametric CAD modeler capable of advanced part modeling, but also fitting for STL editing needs.
The Part tools like Boolean Cut, Fuse, and Common allow precise geometry edits and repair by combining STL objects. The Part Shapebuilder also heals STL meshes by recreating faces and wireframes.
Other repair tools fix mesh errors, remove folds, close holes, and rebuild broken facets. The Sandbox tool enables free-form deformations and filing.
FreeCAD uses constrained sketching coupled to 3D features for parametric modeling. This enables editable designs beyond basic mesh repairs. The Path Workbench can generate 3D printer toolpaths as well.
FreeCAD runs on Windows, Mac, and Linux. The learning curve is higher, but open possibilities for designing precise mechanical parts.
5. SculptGL – Browser-Based Digital Sculpting
For quick STL editing and sculpting online, SculptGL runs right in the browser. It imports OBJ, STL, PLY, and XYZ models.
SculptGL provides an array of digital sculpting brushes supporting additions, deletions, smoothing, inflation, twists, and more. The handy lasso tool selects specific model regions to focus your edits.
Additional tools analyze and repair issues with holes, edges, normals, and geometry. Models can be decimated as well for optimization.
For a web-based app, SculptGL provides great STL editing and sculpting freedom. The interface and tools are intuitive enough for beginner use. No install needed since it runs in modern browsers like Chrome.
6. Tinkercad – Easy Online Editing And Design
Tinkercad offers a simplified online 3D design and STL editing tool from Autodesk. Like SculptGL it runs fully in your web browser with no downloads required.
Tinkercad makes it easy to import STL, OBJ, and other files then manipulate models using the drag-and-drop transform widgets. Edit geometry with the add/remove shapes tools or do boolean operations.
The Surface Editor introduces subdivisions for smoother mesh textures. Additional repair tools identify and patch up holes and disconnections in models.
With its block-based CAD construction and intuitive direct interaction, Tinkercad is ideal for beginner 3D modelers. Easy enough for quick STL edits and repairs too.
7. Simplify3D – Focus On 3D Printability
Simplify3D is premium 3D printing software focused on print preparation and gcode generation. But it also incorporates handy STL editing capabilities.
The model repair tools fix common issues like holes, facets, edges, overlaps, and geometry errors. This ensures models are manifold and watertight before slicing.
Additional modifiers like scaling, embedding, splitting, and processings optimize models for printability. The software also provides full control over supports, rafts, slicing parameters, and other factors.
Simplify3D’s main value is high-quality print preparation for a vast array of machines. But the integrated STL editor can also clean up problematic files.
A license costs $149, so Simplify3D is better suited for advanced users, businesses, and professional 3D printing workflows.
Key Criteria For Picking The Right STL Editor
With those seven options covered, the best STL editor comes down to your specific needs:
- For basic repairs, Meshmixer, 3D Builder, and SculptGL are easy-to-use options.
- If also needing sculpting or parametric modeling tools, Blender and FreeCAD are more capable free choices.
- For pure mesh sculpting and digital clay workflows, try SculptGL or Meshmixer with its sculpting brushes.
- For browser-based online editing, Tinkercad and SculptGL give access anywhere without installing software.
- If pursuing high-quality 3D printing, Simplify3D checks prints for issues and quality control.
Factor your experience level, use cases, and platform requirements when deciding on an STL editor. The good news is there are many full-featured free solutions available.
Fixing STL Files For Successful Prints
Perfectly crafted STL models from 3D modeling software can still cause issues when you go to slice and print them. An STL editor that can quickly find and correct problems provides peace of mind that the model will slice as expected.
Don’t let simple gaps, facets errors, and geometry issues stop your creative 3D printing projects. With the right free STL editor, you can diagnose and repair models in minutes. Getting robust tools like Meshmixer or Blender in your workflow pipeline will save endless headaches.
Prep prints for success and expand your modeling possibilities with the top free STL file editors for 3D printing.
