A .ply file is a PLY file — the Polygon File Format, also called the Stanford Triangle Format. It stores a 3D polygon mesh or point cloud using a self-describing header that can list per-vertex properties such as position, RGB color, normals and confidence. PLY is the de facto standard for 3D scanner output, photogrammetry point clouds and geometry-processing research, and it exists in both ASCII and binary variants.

Format Guide

PLY File Format (.ply)

Stanford's polygon format — per-vertex color, normals, and custom attributes for point clouds and scan data.

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Valve with handwheel (STEP → PLY), rendered from the converted file — **STEP → PLY**Valve with handwheel: 2.2 MB STEP → 5.5 MB PLY, 64,322 triangles, 2.2 s (Ryzen 9 3900X).

Where this format fits

Your file

Solid CAD

STEP
IGES
BREP

Meshes

STL
OBJ
3MF
PLY
glTF
GLB
FBX
DAE
X3D
OFF
AMF

3D faces in drawings and scenes

3D CAD Converteropens, previews, converts

What you get

3D printing

Web, AR and games

glTF
GLB
FBX
DAE

Viewers and archives

VRML
X3D
OFF

CAD exchange

STEP
IGES
BREP

Solid CAD (STEP, IGES, BREP) can become a mesh or another solid format. A mesh converts to other meshes. Dashed formats (DXF, DWG, AMF, USD) can be read but not written. VRML reads .wrl, .vrml and gzipped .wrz files and writes .wrl.

What it will not do

Convert a 2D-only DWG or DXF drawing. It needs 3D faces.
Turn a mesh (STL, OBJ, 3MF) back into STEP, IGES or BREP.
Read native SolidWorks, Inventor or CATIA files. Export STEP or IGES from that program first.

Extension	.ply
Full name	Polygon File Format / Stanford Triangle Format
Geometry type	Polygon mesh with custom per-vertex/per-face attributes
Variants	ASCII, Binary (little-endian), Binary (big-endian)
Open standard	Yes
Supports color	Yes — per-vertex RGB/RGBA
Supports normals	Yes — per-vertex
Supports arbitrary properties	Yes — self-describing header

What is a PLY file?

PLY (Polygon File Format, also known as Stanford Triangle Format) was developed at Stanford University in the 1990s for storing 3D scan data from the Digital Michelangelo Project. PLY uses a flexible, self-describing header that defines which per-vertex and per-face properties the file contains — for example: position, RGB color, normal vector, confidence, intensity. This makes PLY ideal for 3D scanner output, photogrammetry point clouds, and research datasets where geometry comes with rich per-point metadata. PLY exists in ASCII and binary (little-endian or big-endian) variants.

Common Uses of PLY Files

3D Scanning & Point Clouds

Lidar scanners, structured light scanners, and depth cameras (Intel RealSense, Microsoft Azure Kinect) output PLY files with per-point color and normal data.

Photogrammetry Output

Photogrammetry software (Agisoft Metashape, COLMAP, OpenMVS) exports point clouds and dense meshes as PLY files for further processing in MeshLab or CloudCompare.

Research Datasets

The Stanford 3D Scanning Repository (including the famous Stanford Bunny and Dragon models) distributes datasets in PLY format, making it the de facto standard for geometry processing research.

Software Support

MeshLab, CloudCompare, Blender, Open3D, PCL (Point Cloud Library), Assimp, 3D Slicer, and 3D CAD Converter.

Convert This Format

Commonly converted to STL for 3D printing, to OBJ for rendering, or to glTF/GLB for web visualization. Mesh repair is often needed before printing PLY scan data.

How to Convert PLY to STL, OBJ or glTF

PLY is great for capturing 3D scans and point clouds, but most printers, renderers and web viewers expect a different format. 3D CAD Converter reads ASCII and binary PLY (including per-vertex color) and exports clean mesh files in three steps.

Add your PLY files

Drag a single .ply scan or a whole folder into the app. Both ASCII and binary PLY are detected automatically.

Pick an output format

Choose STL for 3D printing, OBJ for rendering, or glTF/GLB for the web. Set tessellation and units if you need a specific scale.

Click Convert

The whole batch is processed locally with a progress bar and ETA. Your scan data never leaves your PC.

Prefer the command line? The same conversions run from the CLI for scripting and automation:

# Convert a PLY scan to STL for 3D printing
cadconvert convert scan.ply -o scan.stl

# Convert a PLY scan to OBJ for rendering
cadconvert convert scan.ply -o scan.obj

# Export a mesh to compact binary PLY
cadconvert convert model.stl -o model.ply --binary

# Batch-convert a whole folder of scans to PLY
cadconvert batch ./in -o ./out -f ply -r

# Reduce a dense scan to half its triangles
cadconvert convert scan.ply -o scan_light.stl --decimate 0.5

PLY is both an import and an export format. Use --binary for compact binary PLY, --units to set the scale and --decimate to cut the triangle count of a dense scan.

PLY: the 3D-scanning and photogrammetry format

PLY earns its place wherever geometry arrives with rich per-point data. Its self-describing header can carry per-vertex RGB color, normals, confidence and intensity, which is exactly what lidar scanners, depth cameras and photogrammetry pipelines produce. That makes PLY the natural container for raw 3D-scan output and dense point clouds — far more so than a printing format like STL, which stores triangles only.

Once a scan is cleaned up, you usually move it on to a more universal mesh format. Compare PLY with its neighbours and convert in one click: STL, OBJ, OFF.

Common PLY Issues (and How to Fix Them)

ASCII vs binary file size

ASCII PLY is human-readable but can be several times larger and slower to load than binary PLY. For big scans, export to binary PLY with --binary to cut file size and speed up downstream tools.

Point cloud vs mesh

A PLY can hold a bare point cloud (vertices only, no faces) or a full mesh. Printing and most renderers need faces — if a converted file looks empty, the source PLY was likely a point cloud that needs meshing first.

Per-vertex color is dropped on STL

STL stores no color, so per-vertex RGB in a PLY is lost when converting to STL. To keep color, convert to OBJ, glTF or 3MF instead, or keep the original .ply as your color master.

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PLY File Format — FAQ

What is a .ply file?

A .ply file is a PLY file — the Polygon File Format, also called the Stanford Triangle Format. It stores a 3D mesh or point cloud with a self-describing header that can list per-vertex position, RGB color, normals and more, in ASCII or binary. It is the de facto standard for 3D scans, photogrammetry and geometry-processing research.

How do I open a PLY file without MeshLab or Blender?

You do not need MeshLab, CloudCompare or Blender just to reuse a PLY. 3D CAD Converter opens .ply files directly — ASCII and binary, with per-vertex color — and exports them to STL, OBJ, glTF and 12+ formats in batch. Drop a file or a folder, pick a format and click Convert.

How do I convert PLY to STL?

Open the .ply in 3D CAD Converter and choose STL, or run cadconvert convert scan.ply -o scan.stl. STL keeps geometry only, so per-vertex color is dropped — expected for 3D printing. Use cadconvert batch ./in -o ./out -f stl -r to convert a whole folder of scans at once.

Can I convert PLY for free?

Yes. 3D CAD Converter has a free trial that converts PLY to STL, OBJ, glTF and more, including binary PLY output and full batch folders, with control over units and tessellation. It covers 10 conversions at full quality with no end date, and no credit card is required on Windows 10 or 11.