Skip to main content
GLBKit

OFF to 3MF Converter

Convert a bare OFF geometry file to a 3MF package for 3D printing. OFF has no colour, so the result is flat. Runs in your browser.

Drag & drop your OFF file here

or click to browse

Supported Formats

.glb.gltf.obj.fbx.stl.ply.3mf.off.zip

Format Information

Source Format

OFF.off

OFF (Object File Format)

OFF is a minimal, human-readable geometry format from the Geomview project: a header line, a count line, then a list of vertex positions and a list of polygon vertex lists. There is deliberately nothing else in the specification.

What it carries: Vertex positions and face index lists, written out as triangles. No normals, no colours, no UVs, no materials, no textures and no animation.

Open a OFF file in the viewer

Target Format

3MF.3mf

3MF (3D Manufacturing Format)

3MF is the modern replacement for STL, built for 3D printing and industrial additive manufacturing. It is an OPC package — a ZIP container holding XML metadata and mesh parts — which is why it can carry colour and material information that STL cannot.

What it carries: Triangle geometry, per-vertex colour and a base material colour. This converter writes geometry and colour; image textures and the wider 3MF material model are not written, and textures inside an imported 3MF are not read.

Open a 3MF file in the viewer

About this conversion

Bare geometry into the modern print format. The OFF triangles are written into a 3MF package, so a minimal vertex/face list becomes a file modern slicers handle properly.

Why convert OFF to 3MF

  • Get bare geometry into a modern slicer or print-farm tool.
  • Store minimal geometry in a container that can grow beyond a triangle list.
  • Move an OFF-based geometry workflow onto 3MF.

What happens during the conversion

Geometry

The vertex positions and faces are triangulated into an indexed mesh and written into the 3MF model part, with transforms baked in. The package is reloaded and validated before download.

Materials and textures

No colour is available — the OFF source has none — so the mesh is written in the single flat colour the OFF reader attaches on load, a lime green (#B8FF3B). UVs and normal maps are not written either.

Common use cases

  • Preparing bare geometry for a modern slicer.
  • Storing minimal geometry in a container that supports colour later.
  • Bridging a geometry-processing workflow and a printing workflow.

Limitations of this conversion

  • No colour survives, because the OFF source has none. Colour only appears if the source mesh already carries it.
  • No UVs or normal maps are written.
  • Normals are dropped, so any shading you see in a slicer comes from re-deriving the face winding.
  • The 3MF that comes out declares its unit as millimetres. Your OFF coordinates are passed through unscaled and OFF carries no unit of its own, so check the size in your slicer before printing.

How to convert OFF to 3MF

Three steps in the browser. Nothing is uploaded to a server, so an unwieldy file is limited only by your own device's memory.

1
STEP 1

Upload your .off

The plain-text OFF file is read directly, and vertex normals are derived from the face winding before the 3MF is assembled.

2
STEP 2

Convert to 3MF

Geometry is triangulated and written into a validated 3MF package.

3
STEP 3

Preview in your slicer

Check the scale and orientation before printing.

Related tools and formats

Frequently Asked Questions

Questions people ask when turning OFF files into 3MF.

Looking for a different direction? See every supported conversion.