Where PLY files come from
If a scanner or a research tool handed you a .ply, this page shows what is inside before you spend filament on it. Triangle meshes are what it draws.
Like STL, PLY has no unit field. The viewer shows the numbers as millimetres, so check the size against something you know, such as a 20 mm hole you measured on the real object.
How the PLY viewer handles a scan
Triangle meshes in PLY are covered by tests: a mesh opens, converts to STL and re-opens with the same size, volume and triangle count. Per-vertex color display is not part of our tests, so treat the shading you see as a geometry check.
- Drop the .ply file or press Open File.
- Read X × Y × Z and the triangle count in Info.
- Look at holes and open edges in the mesh check.
- Use Section to see whether the scan is a closed shell or a single surface.
Scan problems and fixes
Scans are dense and often open. Expect holes where the scanner could not see, loose fragments and a size that is off by a factor.
- Holes. Edit → Repair closes simple holes with a flat fan, good for small or flat gaps; a large curved gap needs a sculpting app. In tests an open box became watertight at 8000 mm³.
- Too many triangles. Reduce to a set %; a test sphere at 30 % kept its volume within 2 %.
- Wrong scale. Set an exact length on one axis in Edit and the rest follows.
- Tab runs out of memory. Above roughly 1 to 2 million triangles this can happen; decimate on the scanning side first.
Cut a large scan into printable parts
A scanned bust or a car part may not fit your bed in one piece. After Repair makes the scan watertight, Edit → Cut with a plane splits it into two closed parts and caps the cut face. Each half saves as its own STL. Cut, booleans and raised text all need a watertight mesh, so the tool asks for Repair first when the scan is open.
Weighing a scanned object
Once the scan is watertight, Info gives volume in cm³ and weight for 17 materials. When you plan to print a replacement part, you learn the filament weight before you slice.
PLY to STL and nearby formats
For printing, PLY to STL saves a binary STL; repair first if the mesh check shows holes. PLY binary is also one of the save targets. So is OFF, another simple mesh format that opens here too. Meshes from modelling tools are usually OBJ, which the OBJ viewer opens, and a scan packed for the web may come as GLB for the GLB viewer. Formats outside this family are on the 3D model viewer hub.
Questions and answers
How do I view a .ply file online?
Open this page in Chrome and drop the file. The scan is read in your tab and is never sent anywhere.
Does the viewer show point clouds?
Our tests cover PLY triangle meshes. A file with vertices only has no faces to draw as a surface, so mesh it first in your scanning software.
Can I save a cleaned scan as PLY again?
Yes, PLY binary is a save target. Convert → PLY writes the repaired mesh.
How big can a PLY scan be?
No hard limit is set; memory is. A 250k-triangle mesh opens in about 1.5 s, and above roughly 1 to 2 million triangles the tab may run out of memory.
Can I print a PLY scan directly?
Your slicer most likely wants STL or 3MF. Repair the holes, check the size, then convert to STL.