What the PLY keeps
- The outer shape of every solid
- Every part in its assembled position
- Coordinates in millimetres
- Vertices and triangle faces, in compact binary
Convert STEP or STP to PLY online
Upload a .step or .stp file and download one binary PLY mesh in millimetres, ready for MeshLab, CloudCompare or Open3D. First 2 files free, any size up to 300 MB. After that, 1 credit per file.
STEP to PLY converter
Binary .plySTEP
From STEP.step or .stp
PLY
binary mesh
Sign in with Google or an emailed code to upload your own file. The sample file works without signing in.
Drop your STEP file here
or browse files
.step or .stp · up to 300 MBFirst 2 conversions free — any size up to 300 MB. Then $2.99 or 1 credit per file, charged at download. Prices include tax.
Starting from a PLY? We also convert in the reverse direction (PLY → STEP).
- Files up to 300 MB
- Binary PLY in millimetres
- Opens in MeshLab and CloudCompare
STEP to PLY converter at a glance
- Converts
- STEP and STP (AP203, AP214, AP242) to PLY.
- You get
- One binary PLY file (little-endian): a single triangle mesh in millimetres, meshed at a 0.15 mm chord tolerance. No colours.
- File size
- Up to 300 MB. We email you when the file is ready.
- Price
- First 2 files free, any size up to 300 MB. After that, 1 credit per file.
How to convert STEP to PLY
STEP to PLY in four steps
To convert STEP or STP to PLY, sign in, upload your .step or .stp file above and download the .ply. You get one binary triangle mesh in millimetres that MeshLab, CloudCompare, Open3D and Blender open. STP to PLY works the same way.
Upload
Sign in, then drop a .step or .stp file up to 300 MB onto the converter.
Convert
Every face is meshed into triangles at a 0.15 mm chord tolerance.
Download
We email you when the PLY is ready. Download one binary .ply.
Check
Open it in MeshLab or CloudCompare and measure one known dimension.
STEP vs PLY
What changes when STEP becomes PLY
STEP stores exact CAD geometry. PLY stores vertices and faces.
What it leaves behind
- Exact curves, which become flat facets
- Feature history, sketches and constraints
- Part names and the assembly tree
- Colours (no per-vertex colour is written)
- The unit label (PLY has no unit field)
Mesh quality
How curves become triangles
PLY stores flat triangles, so every curve becomes a chain of short straight edges.
One setting for every file
We mesh every STEP at a 0.15 mm chord tolerance and about 29° between neighbouring triangles, the same setting we use for STL. There are no quality presets. A part that won't mesh at that setting is re-meshed slightly coarser.
Chord toleranceThe largest gap between the true surface and a triangle.
Angular toleranceThe largest bend between neighbouring triangles. Keeps small holes round.
Compare CAD with a scanLoad the PLY and your scan in CloudCompare, align them and compute cloud-to-mesh distances.
Need ASCII PLY?Open the binary PLY in MeshLab and export it with Binary encoding turned off.
Need points, not a mesh?Sample points on the mesh in CloudCompare or MeshLab.
Choose the right format
STEP vs PLY vs STL
Pick by what the next program needs.
| STEP | PLY | STL | |
|---|---|---|---|
| Geometry | Exact surfaces and solids | Vertices and faces | Triangles only |
| Units | Stored | Not stored (ours is mm) | Not stored |
| Colour | Colours | Per-vertex colour possible (ours has none) | None |
| Storage | Text | Binary or ASCII (ours is binary) | Binary or ASCII |
| Best for | Design, CNC and suppliers | Scans, point clouds and research | 3D printing |
PLYConvert to PLY when
STEPKeep STEP whenThe model is going into MeshLab, CloudCompare, Open3D or a scan-comparison workflow.
You're in the right placeThe part will be machined, edited or quoted from exact CAD geometry.
Open the STEP viewer OBJChoose OBJ whenThe model is going into a renderer or game engine.
STEP to OBJ for renderingOpen it anywhere
Ready for mesh and scan tools
PLY is the common format for scan and point-cloud software.
MeshLabOpens PLY
CloudCompareOpens PLY
Open3DReads PLY
BlenderImports PLY
PCLReads PLY
trimeshReads PLY
Our PLY is binary little-endian, with vertex positions and triangles and no colours or normals. Coordinates are in millimetres.
FAQ
STEP to PLY questions
Binary or ASCII, scans, units, mesh quality, pricing and your files.
Contact usLast updated 6 November 2026How do I convert a STEP file to PLY?
Upload your .step or .stp file to the converter at the top of this page and download one binary PLY mesh in millimetres. You can also open the STEP in FreeCAD, which is free, and export PLY there. Marathon OS is the paid route if you only have the STEP: first 2 files free, then 1 credit per file.
Is the Marathon OS STEP to PLY converter free?
First 2 files free, any size up to 300 MB. After that, 1 credit per file. Credit packs bring it down to $1.80 per file. Prices include tax, you pay only when you click Download and credits never expire.
Can I convert STP to PLY?
Yes. .stp is the short extension for STEP; both convert the same way.
Is the PLY binary or ASCII?
Binary, little-endian: the compact form MeshLab, CloudCompare and Open3D read. If you need ASCII, open it in MeshLab and export with Binary encoding turned off.
Does the PLY include colours?
No. It holds vertex positions and triangles, with no colours. STEP colours don't carry over to PLY.
Can I compare my CAD model with a 3D scan?
Yes. Load the PLY and your scan in CloudCompare, align them and run a cloud-to-mesh distance to see where the scan departs from the CAD.
What units is the PLY in?
Millimetres. PLY has no unit field, so set the unit or scale in the program you open it in if it expects metres.
What mesh settings does the converter use?
Every file is meshed at the same setting: a 0.15 mm chord tolerance and about 29° between neighbouring triangles, the same as our STEP to STL converter. There are no quality presets, and a part that won't mesh at that setting is re-meshed slightly coarser. Need a finer mesh? Export from your CAD program at a smaller deviation.
Do I get a quality report?
Yes. Every conversion comes with a free quality report with 12 checks, including the mesh setting used, the triangle count, a bounding-box match with the STEP, the surface-area ratio, missing area, whether the mesh is watertight and the number of bodies.
Will the assembly stay in separate parts?
Every part keeps its assembled position, merged into one mesh without part names.
Which STEP versions are supported?
STEP files from any CAD program that writes AP203, AP214 or AP242, as .step or .stp, up to 300 MB.
Do I need an account?
To upload your own file, sign in with Google or an emailed code. The sample file works without signing in.
How long does a STEP to PLY conversion take?
It depends on the part. Large assemblies can take several minutes, and we email you when the file is ready.
Are my STEP files private?
Uploads and downloads use HTTPS. Uploaded and converted files are deleted automatically after 7 days, and converted files aren't added to the public CAD library unless you publish them. You keep ownership of your design. See the Privacy Policy.
Convert your STEP file to PLY
One binary PLY mesh in millimetres, ready for MeshLab, CloudCompare and Open3D. First 2 files free, any size up to 300 MB. After that, 1 credit per file.
Pricing
Pay as you go, cheaper by the pack
Your first 2 CAD file conversions are free, any size up to 300 MB, including the download. From conversion 3 on, each file costs 1 credit or a one-time payment, charged only when you click Download. 1 credit downloads any file up to 300 MB, and credits never expire.
Starter
3credits
$7.99
$2.66 each
3 downloads of any size. Good for a one-off project.
Pro
5credits
$12.99
$2.60 each
5 downloads of any size. The everyday choice.
Team
10credits
$19.99
$2.00 each
10 downloads of any size. Best balance of price and volume.
Studio
15credits
$26.99
$1.80 each
15 downloads of any size. Lowest price per file.
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