STLFixer is a free browser-based tool for inspecting STL files and trying basic mesh repairs. No account or installation is needed.

Why I built it

The idea came from spending time at my brother’s place, playing around with his 3D printer. Some of the model files he had downloaded were damaged, and we ended up troubleshooting files before we could get to the fun part. I wanted a simple way to check a model and attempt a repair in the browser.

How to use it

Open STLFixer, choose an STL file, and inspect the model. Try the available repair options where appropriate, then check the result in your slicer before printing. Keep a copy of your original file so you can compare the results.

A quick note on limits

STLFixer will not fix every broken model. Some files need more involved work in a dedicated modeling tool, and a repaired file does not guarantee a successful print.

I’m Geber, the developer behind STLFixer. If you try it, I’d love to hear what was useful and what was confusing.

For inspecting a mesh and making manual geometry edits. Blender is a free, open-source desktop modeling application; the 3D Print Toolbox extension helps identify mesh problems that can affect slicing.

Use it when you need to understand and edit the geometry rather than only run an automatic repair. Install the extension from the official Blender Extensions directory, inspect the model, and review any changes before exporting.

Trade-off: learning Blender takes time. A clean check does not guarantee a successful print; check the exported file in your slicer. This is an independent third-party tool, not a product I developed.

For inspecting and cleaning triangular meshes, especially scanned or otherwise messy models. MeshLab is a free, open-source desktop mesh-processing tool with cleaning, healing and inspection features.

Use it when a model needs more detailed mesh processing than a quick browser check. Work on a copy, choose filters for the specific problem, and compare the result with the original before exporting.

Trade-off: filters can alter the geometry, and the workflow takes practice. Verify dimensions and inspect the result in your slicer. MeshLab is an independent open-source project; I am not its developer.

For checking how a model will slice and handling some mesh errors during print preparation. PrusaSlicer is a free, open-source desktop slicer from Prusa Research. Its documentation notes that it can repair models automatically to a certain degree, but some damaged files need a dedicated repair tool.

Import your STL, check warnings, then inspect the sliced layers for missing surfaces or unexpected gaps before printing.

Trade-off: automatic repair is limited. Do not assume a model is correct simply because it imports. Some repair options depend on the operating system and version. This is a third-party tool, not my own product.

For reviewing a model in the context of print preparation, including slicing, supports and printer settings. OrcaSlicer is a free, open-source desktop slicer with a model-repair workflow documented in its official wiki.

Use it to inspect the sliced result after a mesh repair, check the planned layers and supports, and prepare the print for a supported printer. Use the official website or linked GitHub releases for downloads.

Trade-off: slicing and repair cannot solve every geometry problem; difficult cases may need a dedicated mesh editor. Available repair behavior can vary by platform and release. OrcaSlicer is developed by its own community; I am not its developer.