Drop an STL hereor click to browse (binary or text)
Triangles in–
CAD faces out–
Watertight–
Volume (units³)–
0 only merges triangles that are exactly flat. Raise it a little (try 0.01) for scans or sloppy exports. Large values can break the solid.
Drag: orbit · Right-drag: pan · Scroll: zoom
What it does
- Repairs the mesh: welds vertices, removes degenerate and duplicate triangles, fixes winding, fills small holes.
- Merges flat, connected triangles into single planar faces, with holes kept as holes.
- Exports a closed solid as STEP (AP214), which Fusion 360, FreeCAD and SolidWorks open as a body you can cut, combine and measure.
- Use CAD faces in the viewer to see exactly which regions were merged.
What it does not do
- Curved surfaces stay faceted. Cylinders, fillets, spheres and freeform shapes remain many small flat faces. Only planes are recognised.
- It does not rebuild parametric features or a sketch history.
- It cannot make a solid from a mesh that is badly open; the status above tells you if the repair fell short.
- Hole filling is simple and can look wrong on large or concave holes.
Before you rely on it
- Best for mechanical parts with mostly flat faces: brackets, enclosures, blocks. Organic or sculpted models (armor, figures, scans) will export, but mostly as dense triangle faces.
- Units: STL files carry no units. The STEP is labelled millimetres and numbers are unchanged. If your model was in inches, scale it in your CAD tool.
- Check the result in your CAD tool before using it for manufacturing, printing or anything safety-related. Verify dimensions and volume.
- Large files are limited by your browser's memory. Hundreds of thousands of triangles can be slow.
- Privacy: conversion happens locally on your device. Nothing is uploaded or stored.
- Provided as is, with no warranty. Free and open source (MIT).