OneTaskBy Tim King · Updated
PLY to STL
3D Scans to Printable STL, Free
OneTask is free, with no sign-up, and built by one person.
If this tool saved you time, a coffee helps keep new ones coming.
How the PLY To STL works
This PLY to STL converter turns a 3D scan or mesh saved as .ply into an STL your slicer can print. Drop the file, check which way is up in the viewport, scale it to millimetres if the scanner saved metres, and download a binary or ASCII .stl. The scan never leaves your browser, which matters for scans of people and private objects.
PLY to STL: scans to prints
PLY, the Stanford polygon format, is what most photogrammetry apps, phone LiDAR scanners and desktop 3D scanners export. It can store vertex colours and other properties alongside the faces. STL keeps only the triangles. The converter reads binary and ASCII PLY, applies the up axis and scale you choose and writes the faces as STL, dropping colour because STL has no place for it.
Point clouds cannot be converted directly
Some PLY files hold only points, with no faces joining them. The viewport shows these as a cloud of dots, and the converter refuses them, because there are no triangles to print. Mesh the cloud first in the scanning app or in a tool such as MeshLab, using Poisson or ball-pivoting surface reconstruction, then convert the meshed PLY.
Scale and orientation
Scanners and photogrammetry apps usually save in metres, while slicers read millimetres, so a scanned mug arrives 0.1 mm tall. Choose m to mm to fix it. Scans are often tilted or upside down as well; switch the up axis until the preview stands up, and do any finer rotation in the slicer.
Before you print a scan
Raw scans have holes where the scanner could not see, a ragged base and far more triangles than a printer needs. Fill holes and flatten the base before printing, and decimate scans over a few million triangles so the slicer stays responsive.
FAQ
Why does it say my PLY is a point cloud?
The file has vertices but no face list, so there is no surface to turn into triangles. Run surface reconstruction in your scanning app or MeshLab to build a mesh, save it as PLY again and convert that.
Are vertex colours kept?
No. STL cannot store colour, so the result is a single-colour solid. If you need a colour 3D print, export the scan as 3MF or OBJ with textures from your scanning software instead.
How large a scan can it convert?
Scans of a few million triangles convert in seconds on a modern computer. Very dense scans may use a lot of memory in the browser tab; decimate them first if the page becomes slow.
See also: all Images tools, Units, Audio & Video, Documents, Data & Code.
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