AnyFormat

00 STL → PLY

STL to PLY

The format MeshLab, CloudCompare and Open3D prefer.

01STL in
02PLY out
03Options 5

STL repeats every vertex once per triangle. Merging typically cuts the vertex count by two thirds.

Vertices closer together than this are treated as one.

glTF works in metres and the printing formats in millimetres. Leave this on unless your model comes out a thousand times the wrong size.

Multiplied on top of any unit conversion. Use 25.4 to turn inches into millimetres.

  • No upload The conversion runs in this tab. Your file never travels — not to us, and not to the advertising.
  • No sign-up, no email, no daily cap There is no account system to sign up to.
  • No size limit we invented Only your device's memory — about ~2 GB on a desktop browser, ~400 MB on a phone.
  • Turn your Wi-Fi off and convert anyway The conversion needs nothing but this page. Ads will not load without a connection; your file will still convert. That is the whole claim, and it takes five seconds to check.

Converts STL to PLY. PLY is the format of scanning and research tooling — MeshLab, CloudCompare, Open3D and most photogrammetry pipelines — largely because it can carry arbitrary per-vertex data that STL cannot.

What PLY adds

PLY's header declares whatever properties the file carries, so beyond position it can hold per-vertex colour, normals, confidence values, intensity — anything a scanner records. STL has room for none of it.

Converting from STL does not invent that data, of course. What you gain is a format that can hold it once a tool downstream computes it, and that indexes vertices rather than repeating them.

One STL extension does carry over: some slicers store a colour in the unused attribute field of each binary triangle. Where that is present it is read and written as per-vertex colour, and you are told it happened.

ASCII or binary

ASCII is readable and diffable and roughly three times larger. Binary little-endian is what MeshLab and CloudCompare write by default and what you want for anything sizeable. Both are read back by every PLY tool.

STL repeats every vertex three times

An STL is a bag of triangles with no notion that two of them might share a corner, so a cube that needs 8 vertices is stored as 12 triangles carrying 36 of them. The conversion preserves that structure rather than welding coincident vertices, because welding needs a distance tolerance and the right tolerance depends on the model — too tight and nothing joins, too loose and thin walls collapse into each other. So expect the PLY to be about the same size, and weld deliberately in a mesh editor where you can see what it did.

Other names for this

Also searched as “stl to polygon file format”.

Questions

Why would I use PLY over OBJ?
Per-vertex colour and arbitrary per-vertex attributes, which OBJ cannot express. It is also what scanning and point-cloud tools expect.
Will my model have colour?
Only if the STL used the non-standard attribute-field colour extension, which some slicers write. Otherwise there is no colour to carry.
Is my model uploaded?
No. The parsing and rewriting happen in this tab. Models are frequently confidential — an unreleased product, a client’s part, a scan of something proprietary — and none of it is transmitted. Turn your Wi-Fi off and the tool keeps working.
How large a model can I convert?
There is no imposed limit; the ceiling is your device’s memory. A desktop browser handles files of roughly 2 GB and a phone about 400 MB. A 200 MB STL — around four million triangles — converts in a few seconds on a laptop.