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OFF (.off, .coff)

  • Import and Export support ASCII and binary versions of the OFF file format.

Background & Context

    • OFF 3D geometry format.
    • Used for storing and exchanging 3D models.
    • OFF is an acronym for Object File Format.
    • Occasionally called COFF if color information is present.
    • Related to NOFF and CNOFF.
    • ASCII or binary format.
    • Represents a single 2D or 3D object.
    • Stores a collection of planar polygons with possibly shared vertices.
    • Supports polygon and vertex colors and opacity specifications.

Import & Export

  • Import["file.off"] imports an OFF file as a MeshRegion object representing the surface.
  • Import["file.off",elem] imports the specified element from an OFF file.
  • The import format can be specified with Import["file","OFF"] or Import["file",{"OFF",elem,…}].
  • Export["file.off",expr] exports a 3D mesh-based geometric region to a binary OFF file. The expr can be any region that is ConstantRegionQ or a Graphics or Graphics3D object.
  • Export["file.off",expr,{opt1->val1,…}] exports expr with the specified options for the file format.
  • The export format can be specified with Export["file",expr,"OFF"] or Export["file",expr,{"OFF",opt1->val1,…}].
  • See the following reference pages for full general information:
  • Import, Exportimport from or export to a file
    CloudImport, CloudExportimport from or export to a cloud object
    ImportString, ExportStringimport from or export to a string
    ImportByteArray, ExportByteArrayimport from or export to a byte array

Import Elements

  • General Import elements:
  • "Elements" list of elements and options available in this file
    "Summary"summary of the file
    "Rules"list of rules for all available elements
  • Data format representation elements:
  • "BinaryFormat"whether the file is a binary or ASCII OFF
    "VertexData"list of vertex coordinates
    "PolygonData"the polygon elements in indexed form
    "VertexColors"colors associated with each vertex
    "PolygonColors"face color information for each polygon
  • Geometry representation elements:
  • "BoundaryMeshRegion"boundary mesh representation of the solid
    "MeshRegion"mesh representation of the surface
  • Graphics representation elements:
  • "Graphics"2D OFF file represented as a Graphics object
    "Graphics3D"3D geometry represented as a Graphics3D object
    "GraphicsComplex"OFF file as a GraphicsComplex object
    "PolygonObjects"list of Polygon primitives given in absolute coordinates

Options

  • Export options:
  • "BinaryFormat"Truewhether to write a binary or ASCII file

Examples

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Basic Examples  (2)

Import a 3D model from OFF as a MeshRegion object:

Wolfram Language code: Import[ "ExampleData/seashell.off"]

Summary properties of the model:

Wolfram Language code: Import["ExampleData/seashell.off", "Summary"]

Export a 3D model to an OFF file:

Wolfram Language code: Export["model.off", [image], "BinaryFormat" -> False]

Print the raw textual contents of the file:

Wolfram Language code: FilePrint[%]

Scope  (13)

Import  (7)

Import works on an ASCII OFF file:

Wolfram Language code: Import["ExampleData/seashell.off"]

Binary OFF file:

Wolfram Language code: Import["ExampleData/spikey.off"]

Any accessible URL:

Wolfram Language code: Import["http://exampledata.wolfram.com/vase.off"]

Stream:

Wolfram Language code: str = OpenRead["ExampleData/chain.off"]
Wolfram Language code: Import[str]
Wolfram Language code: Close[str]

Import automatically detects OFF files:

Wolfram Language code: Import["http://exampledata.wolfram.com/gear.4"]

Import provides access to elements in the OFF file:

Wolfram Language code: Import["ExampleData/seashell.off", "Elements"]

Import works on large files:

Wolfram Language code: Import["http://exampledata.wolfram.com/turtle.off"] // MeshCellCount//AbsoluteTiming

Export  (6)

Export works on 3D graphics:

Wolfram Language code: Export["model.off", [image]]

Special regions:

Wolfram Language code: Export["sphere.off", Sphere[]]

Formula regions:

Wolfram Language code: Export["ball.off", ImplicitRegion[x ^ 2 + y ^ 2 + z ^ 2 ≤ 1, {x, y, z}]]

Mesh regions:

Wolfram Language code: Export["pyramid.off", MeshRegion[{{-1, -1, 0}, {1, -1, 0}, {1, 1, 0}, {-1, 1, 0}, {0, 0, 1}}, Pyramid[{1, 2, 3, 4, 5}]]]

Export to a binary OFF file:

Wolfram Language code: Export["model.off", [image]]

ASCII OFF file:

Wolfram Language code: Export["model.off", [image], "BinaryFormat" -> False]

Import Elements  (11)

"BinaryFormat"  (1)

Test whether this file is a binary or ASCII OFF:

Wolfram Language code: Import["ExampleData/seashell.off", "BinaryFormat"]

"BoundaryMeshRegion"  (1)

Give a boundary mesh region:

Wolfram Language code: Import["ExampleData/chain.off", "BoundaryMeshRegion"]

"CoordinateTransform"  (1)

The coordinate system used by the OFF format is identical to the Wolfram Language:

Wolfram Language code: Import["ExampleData/chain.off", "CoordinateTransform"]

"Graphics3D"  (1)

Give the Graphics3D object:

Wolfram Language code: Import["ExampleData/chain.off", "Graphics3D"]

"GraphicsComplex"  (1)

Give the GraphicsComplex object:

Wolfram Language code: Import["ExampleData/chain.off", "GraphicsComplex"]

"MeshRegion"  (1)

Give a mesh region:

Wolfram Language code: Import["ExampleData/chain.off", "MeshRegion"]

"PolygonColors"  (1)

Give the polygon colors:

Wolfram Language code: Import["ExampleData/seashell.off", "PolygonColors"]//Short

"PolygonData"  (1)

Give the polygon elements in indexed form:

Wolfram Language code: Import["ExampleData/chain.off", "PolygonData"]

"PolygonObjects"  (1)

Give the list of Polygon primitives given in absolute coordinates:

Wolfram Language code: Import["ExampleData/chain.off", "PolygonObjects"]

"Summary"  (1)

Give the summary of properties:

Wolfram Language code: Import["ExampleData/chain.off", "Summary"]

File size:

Wolfram Language code: %["FileSize"]

"VertexData"  (1)

Give the vertex coordinates:

Wolfram Language code: Import["ExampleData/chain.off", "VertexData"]//Short

Export Options  (2)

By default, a binary file is generated when exporting:

Wolfram Language code: Export["model.off", [image]]

Print the raw textual contents of the file:

Wolfram Language code: FilePrint[%]

Use "BinaryFormat" False to generate an ASCII file:

Wolfram Language code: Export["model.off", [image], {"OFF", "BinaryFormat" -> False}]

Print the raw textual contents of the file:

Wolfram Language code: FilePrint[%]