Browser-local converter
STL to PLY converter
Convert an STL into a Stanford PLY on your own machine, for MeshLab, CloudCompare, research tooling or anything else that prefers PLY. Both ASCII and binary little-endian output are offered, and the file is checked by re-opening it.
Drop your STL files here
STL, OBJ, PLY, GLB, glTF, 3MF, SVG and DXF. Nothing is uploaded: files are read and converted inside this tab. Checking what this device can handle...
Queue
No files yet. Drop models above, or use the file picker.
Output
Units
Size and placement
Repair and cleanup
These can change the shape, so they need a before-and-after review before export.
Inspection
Add a model to see its dimensions, mesh health and estimated volume.
What this STL to PLY conversion does and does not do
- An STL is a triangle soup with three unshared vertices per triangle. Written straight through, the PLY has a needlessly large vertex list; weld first and it typically drops by around two thirds.
- STL has no colour, so the PLY is written without per-vertex colour. Many tools expect colour in a PLY from a scanner, and inventing it here would be dishonest.
- Neither format records a unit, so coordinates are copied across unchanged and keep whatever meaning they already had.
- Normals and uv coordinates are written only when every part of the scene carries them, because a PLY header that promises a property some vertices lack is a file that lies about itself.
- Binary output is little-endian. Big-endian PLY is read but never written, since nothing in current use requires it.
Troubleshooting
The PLY has three times the vertices I expected
That is STL doing its job badly: every triangle owns its own three vertices. Run weld with the suggested tolerance before exporting.
My tool wants per-vertex colour
STL has no colour channel to convert from. If you need coloured PLY, the colour has to come from the original scan or model, not from a format conversion.
The file is huge
Export binary rather than ASCII. Binary PLY is several times smaller and parses faster, and both forms are validated identically here.
The surface looks faceted
STL stores no smooth normals. Recalculate normals with smoothing before exporting and the PLY will carry per-vertex normals.
Questions
ASCII or binary PLY?
Binary little-endian unless you specifically need to read the file by eye. It is smaller and faster, and every tool that reads PLY reads it.
Is the triangle count preserved?
Exactly, and it is verified. The PLY is re-parsed after writing and its triangle count, mesh count and bounding box are compared against the source.
Why use PLY rather than STL?
PLY has a real vertex list with shared vertices, an extensible property system and both text and binary forms. It is the better container for scan and research data; STL persists because slicers accept it.