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Supported Formats

Overview

Format Extension Default Best For
STL .stl ✓ 3D printing
STEP .step ✓ CAD interchange
3MF .3mf ✓ Modern 3D printing
OBJ .obj Game engines
IGES .iges Legacy CAD
BREP .brep OpenCASCADE
PLY .ply 3D scanning
AMF .amf Additive manufacturing

Format Details

STL (Stereolithography)

Extension: .stl Default: Yes

The most widely supported 3D printing format. Stores only geometry as triangular mesh.

Pros:

  • Universal support in all slicers
  • Simple format, small file size
  • Fast to process

Cons:

  • No color or material information
  • No units (assumed mm usually)
  • No metadata

Best for: 3D printing, rapid prototyping

STEP (Standard for Exchange of Product Data)

Extension: .step Default: Yes

ISO standard for CAD data exchange. Preserves exact geometry (BREP).

Pros:

  • Exact geometry preservation
  • Editable in CAD software
  • Industry standard

Cons:

  • Larger file sizes
  • Not suitable for 3D printing directly

Best for: Sharing with other CAD users, engineering collaboration

3MF (3D Manufacturing Format)

Extension: .3mf Default: Yes

Modern 3D printing format developed by Microsoft and industry consortium.

Pros:

  • Supports color and materials
  • Includes metadata (units, author, etc.)
  • Smaller than STL for same quality
  • Better error handling

Cons:

  • Newer format, not universally supported
  • Some slicers have limited 3MF support

Best for: Modern 3D printing with metadata, color prints

OBJ (Wavefront)

Extension: .obj Default: No

Standard format for 3D graphics and game engines.

Pros:

  • Supports materials (MTL files)
  • Wide support in 3D software
  • Human-readable ASCII format

Cons:

  • No native color support without MTL
  • Large file sizes for ASCII version

Best for: Game engines, 3D graphics, visualization

IGES (Initial Graphics Exchange Specification)

Extension: .iges Default: No

Older CAD interchange format, predecessor to STEP.

Pros:

  • Wide legacy support
  • Preserves curves and surfaces

Cons:

  • Outdated standard
  • Can lose some geometry details
  • Larger than STEP

Best for: Legacy CAD systems, older software compatibility

BREP (Boundary Representation)

Extension: .brep Default: No

OpenCASCADE native format for exact geometry.

Pros:

  • Exact geometry preservation
  • Native FreeCAD format
  • No conversion losses

Cons:

  • Only works with OpenCASCADE-based software
  • Not widely supported

Best for: FreeCAD archives, OpenCASCADE workflows

PLY (Polygon File Format)

Extension: .ply Default: No

Stanford format commonly used in 3D scanning.

Pros:

  • Supports vertex colors
  • Simple ASCII or binary format
  • Good for point clouds

Cons:

  • No material support
  • Less common in CAD

Best for: 3D scanning, point clouds, research

AMF (Additive Manufacturing File Format)

Extension: .amf Default: No

XML-based format designed for additive manufacturing.

Pros:

  • Supports color and materials
  • Curved surfaces (not just triangles)
  • Units included in format

Cons:

  • Limited slicer support
  • Large file sizes (XML)

Best for: Advanced 3D printing features, color printing

Export Methods

Format Export Method
STL Mesh tessellation → Mesh.write()
STEP Part.Shape.exportStep()
3MF Mesh tessellation → Mesh.write()
OBJ Mesh tessellation → Mesh.write()
IGES Part.Shape.exportIges()
BREP Part.Shape.exportBrep()
PLY Mesh tessellation → Mesh.write()
AMF Mesh tessellation → Mesh.write()

Multiple Objects

When multiple objects are selected:

  • Mesh formats: Objects are combined into a single compound mesh
  • CAD formats: Objects are combined into a Part.Compound