Browser-based conversion
Use the converter without installing desktop software to move from OFF to PLY.
Free under 5 MBOFF → PLYNo software installation
Convert OFF
to PLY online
Convert an OFF (.off) mesh into PLY online. Upload your file in the browser and download the converted result without installing desktop CAD software.
Encrypted uploads Files up to 300 MB Deleted after 7 days
Upload your OFF file
Choose one file to begin the conversion.
Drag and drop your 3D file here
or choose a file from your computer
Browse filesMaximum file size: 300 MB
Files under 5 MB convert and download free. For larger files, 1 credit = one download of any size — buy a pack.
Don't have a file? Try a sample:
Built for scan / polygon data
Translate polygon vertices and faces into the vertices, faces and optional point data used by PLY.
Ready for the next workflow
Open the result in MeshLab, scanners and geometry-processing tools for review, editing or production.
Private file handling
Converted models are not added to the public CAD library and are removed after processing.
Continue your CAD workflow
Explore Marathon
OS CAD resources
Preview a model before conversion, find an existing engineering file, open a 2D drawing, or get specialist help when a source mesh needs to be rebuilt.
Browse CAD modelsSearch ready-to-use engineering and 3D-printing files across the Marathon OS library.Browse 2D technical drawingsExplore PDF, SVG and DXF drawing resources for engineering review and documentation.Get CAD design supportWork with a vetted designer when the model needs repair, remodelling or a production-ready native file.
Simple conversion workflow
How to convert OFF to PLY online
Move from OFF mesh to PLY mesh in three clear steps.
Upload your OFF file
Drag and drop the .off file into the converter or choose it from your device. Files up to 300 MB are supported.
Use PLY as the output
This page is preconfigured for OFF-to-PLY conversion, so you do not need to search through target formats.
Download and inspect the PLY
Download the result and open it in your preferred compatible application to confirm its geometry and scale.
Format behaviour
What changes when
OFF is converted to PLY?
OFF and PLY describe geometry differently. Conversion preserves compatible shape and topology while translating or omitting format-specific data.
Normally retained
- Overall model shape
- Compatible geometry
- Model orientation
- Supported topology and layers
May not be retained
- Format-specific metadata
- Unsupported materials or textures
- Application-specific features
- Data without a target-format equivalent
OFF meshOFFPLY meshPLYKeep the original OFF file as the source of truth and inspect the converted PLY file before downstream production use.
Format comparison
OFF versus PLY
Choose the output according to what the next stage of your workflow needs.
| Feature | OFF OFF | PLY PLY |
|---|---|---|
| Main purpose | Geometry research, mesh processing and interchange | 3D scanning, point clouds and mesh interchange |
| Geometry | Polygon vertices and faces | Vertices, faces and optional point data |
| Textures and UV mapping | Not normally supported | Vertex colours may be supported |
| Materials | Not normally supported | No standard material workflow |
| Object groups | Single geometry-oriented dataset | Limited object hierarchy |
| Common workflow | Research and computational geometry tools | MeshLab, scanners and geometry-processing tools |
Choose PLY when
Your next application or supplier specifically requires a PLY file.
3D scanning, point clouds and mesh interchange is the next stage of the workflow.
The target geometry representation suits the downstream task.
Keep OFF when
Your project still depends on data unique to the source format.
You need to continue editing in Research and computational geometry tools.
The model is still being prepared rather than handed off.
Before continuing
Check the converted
PLY before the next step
Changing the file format does not automatically make a model production-ready. Review these checks in the application used for your next workflow.
Important: File formats may not include a standard unit definition. Always verify dimensions after conversion.
- 01
Verify dimensions and scale
Confirm that the converted PLY file uses the expected size and unit interpretation.
- 02
Inspect the complete geometry
Check that all expected bodies, surfaces, curves or drawing entities are present.
- 03
Review surface orientation
Look for flipped faces, inconsistent normals or reversed boundaries after conversion.
- 04
Check topology and open edges
Inspect gaps, overlaps, invalid edges and disconnected geometry before downstream use.
- 05
Confirm layers and object structure
Verify that supported layers, groups and model organisation were translated as expected.
- 06
Open the file in its target application
Preview the PLY result in the software used for the next workflow before production use.
Common problems
OFF-to-PLY conversion troubleshooting
Most conversion issues come from differences between file formats or problems already present in the source geometry.
The PLY file has the wrong size
The source and destination tools may interpret units differently. Open the PLY file and select the correct unit or scale.
Fix: Verify units and dimensionsTextures or materials disappeared
This can be expected when PLY does not support the texture, UV or material information stored by OFF.
Fix: Keep the original OFF visual dataThe model has missing faces
The OFF source may contain open edges, invalid polygons, overlapping geometry or inverted normals that remain visible after conversion.
Fix: Inspect and repair the source geometryThe conversion fails on a large file
High polygon counts and complex geometry need more processing. Confirm the file is below 300 MB and opens correctly in a viewer.
Fix: Simplify unnecessary geometry detailSecure processing
Your 3D files remain yours
Product models can contain confidential engineering information. Privacy and file handling stay explicit beside the tool.
Encrypted upload
Files are transferred through a secure connection.
Automatic deletion
Uploaded and converted files are deleted after 7 days.
You retain ownership
Conversion does not transfer ownership of your model.
Not publicly listed
Your uploaded files are not added to the Marathon CAD library.
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Frequently asked questions
Everything to know before converting
Quick answers about formats, pricing, file limits, conversion quality and privacy.
How do I convert OFF to PLY online?
Upload your OFF file (.off) to Marathon OS, choose PLY as the output format, and download the converted file in seconds — no software installation required.
Why convert OFF to PLY?
Converting OFF to PLY helps you move CAD data between tools, suppliers, and workflows without installing desktop software. Marathon OS handles the conversion in the cloud so you can download a PLY file in seconds.
What OFF and PLY file extensions are supported?
This converter accepts .off input files and outputs .ply. Upload up to 300 MB per file.
Is the OFF to PLY converter free?
Files under 5 MB are free to convert and download on Marathon OS. Larger files may require a small fee per conversion.
How is my data stored and secured?
Your files are encrypted during upload, processed securely in the cloud, and automatically deleted after 7 days.
Do I need any special software or training?
No — upload your OFF file and download PLY directly in your browser. No plugins or desktop CAD tools required.
Can I convert large OFF models to PLY?
Yes — Marathon OS is optimized for large and complex CAD models. You can upload files up to 300 MB for OFF to PLY conversion.
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