STL → PLY · FREE · NO UPLOAD
STL to PLY Converter — Stanford Triangle Format for MeshLab
Turn a .stl into a binary .ply for MeshLab, CloudCompare and scanning pipelines — in the browser, nothing uploaded.
What it does: converts an STL to binary PLY (Stanford Triangle Format) with indexed vertices and face records — the format MeshLab, CloudCompare, and photogrammetry pipelines expect.
Why you need it:PLY is the standard interchange format for scanning and point-cloud tools. STL's repeated-vertex layout wastes space and lacks the header extensibility PLY provides.
How it works: three.js indexes the mesh and writes binary PLY with vertex positions and face indices. No server, no upload — disconnect and it still runs.
Conversion specs
| Input format | STL (binary or ASCII) |
| Output format | Binary PLY (Stanford Triangle Format) |
| Vertex indexing | Shared vertices stored once — smaller output |
| Face records | Written — this is an indexed mesh PLY, not a point cloud |
| Vertex colors | Not added (STL carries no color data) |
| File size limit | Device RAM only — no server limit |
| Processing | 100% client-side via three.js PLYExporter |
| Cost | Free, unlimited conversions, no account required |
From STL to PLY
PLY (Polygon File Format / Stanford Triangle Format) stores vertex positions and face indices. Converting from STL gives you the same triangles in an indexed format that tools like MeshLab, CloudCompare, and photogrammetry pipelines expect. The PLY will not have vertex colors — STL has no color data to pass through.
Drop the STL on the converter above. The preview is the geometry that will go into the PLY: same triangles, re-indexed so shared vertices are stored once. Download binary PLY when the preview looks right. OBJ and GLB are offered as extra downloads if the next tool prefers those instead.
Going the other way — a scan mesh toward the printer — is the PLY to STL converter.
FAQ
Is the STL uploaded to convert it?+
No. Parsing the STL and writing the PLY both happen in this tab with JavaScript. There is no upload endpoint; the tool works offline once the page has loaded.
What is a PLY file?+
PLY is the Polygon File Format, also called the Stanford Triangle Format. It stores vertex positions, face indices, and optionally vertex colors, normals, and UVs. ASCII and binary variants exist. Scanners, MeshLab, CloudCompare, and photogrammetry pipelines use it because a single file can carry an indexed mesh (and, when the source has them, per-vertex colors).
Does the PLY keep vertex colors?+
No — STL has none to give. STL stores only triangles: three vertices and a normal, nothing else. The converter writes an indexed PLY of the same geometry. Tools that expect colored PLY from a scanner will still open this file; they just will not find RGB on the vertices.
Is the PLY binary or ASCII?+
Binary. Binary PLY is smaller and what MeshLab, CloudCompare, and most research tools expect by default. ASCII PLY is human-readable but much larger; this converter does not write it.
Why convert STL to PLY?+
Scanning pipelines, MeshLab workflows, and research tools often expect PLY rather than STL. Converting gives you the same triangles in an indexed format those tools load natively — without a desktop exporter in the middle.
Related: PLY to STL (the reverse), STL to OBJ for editors, STL to GLB for web and AR.