NOFF (.noff, .cnoff)

Background

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

Import & Export

  • Import["file.off"] imports a NOFF file as graphics.
  • Export["file.off",expr] exports graphics to a binary NOFF file.
  • For NOFF files representing a 3D object, Import["file.off"] returns an expression of the form Graphics3D[ GraphicsComplex[vertices,primitives,opts]].
  • Planar objects are imported as Graphics[ GraphicsComplex[vertices,primitives,opts].
  • Import["file.off",elem] imports the specified element from a NOFF file.
  • Import["file.off",{elem,suba,subb,}] imports a subelement.
  • Import["file.off",{{elem1,elem2,}}] imports multiple elements.
  • The import format can be specified with Import["file","NOFF"] or Import["file",{"NOFF",elem,}].
  • Export["file.off",expr,elem] creates a binary NOFF file by treating expr as specifying element elem.
  • Export["file.off",{expr1,expr2,},{{elem1,elem2,}}] treats each expri as specifying the corresponding elemi.
  • Export["file.off",expr,opt1->val1,] exports expr with the specified option elements taken to have the specified values.
  • Export["file.off",{elem1->expr1,elem2->expr2,},"Rules"] uses rules to specify the elements to be exported.
  • See the reference pages for full general information on Import and Export.
  • ImportString and ExportString support the NOFF format.

Import Elements

  • General Import elements:
  • "Elements"list of elements and options available in this file
    "Rules"full list of rules for each element and option
    "Options"list of rules for options, properties, and settings
  • Data representation elements:
  • "Graphics"2D NOFF file represented as a Graphics object
    "Graphics3D"3D geometry represented as a Graphics3D object
    "GraphicsComplex"NOFF file as a GraphicsComplex object
    "PolygonColors"face color information, given as a list of color primitives associated with each polygon
    "PolygonData"the polygon elements in indexed form
    "PolygonObjects"list of Polygon primitives given in absolute coordinates
    "VertexColors"colors associated with each vertex, given as a list of color primitives
    "VertexData"list of vertex coordinates
    "VertexNormals"normal vectors corresponding to the vertices given by "VertexData"
  • Import and Export by default use the "Graphics3D" element to represent 3D geometries and the "Graphics" element for 2D objects.
  • The "VertexData" element corresponds to the first argument of GraphicsComplex.

Options

  • General Import options:
  • BackgroundAutomaticwhat background color to use
    ImageSizeAutomaticoverall size of the graphics to display
    LightingAutomaticwhat simulated lighting to use in coloring 3D surfaces
  • All options of Graphics3D can be given when importing from NOFF.
  • Detailed property:
  • "BinaryFormat"Truewhether the file is in ASCII or binary format
  • Binary NOFF files store information as "Integer32" and "Real32" data types, always using the setting "ByteOrdering"->1.
  • Advanced options:
  • "InvertNormals"Falsewhether to invert the orientation of vertex normals
    "VerticalAxis"{0,0,1}orientation to assume for the coordinate system used in the file
  • By default, the Wolfram Language assumes that in the coordinate system used by the NOFF format the vertical axis corresponds to the third coordinate.
  • With the setting "VerticalAxis"->{0,1,0}, the Wolfram Language will apply the transformation {x,y,z}->{x,-z,y} to all graphics coordinates when importing from NOFF, and the inverse transformation when exporting to NOFF.

Examples

Basic Examples  (3)

Import the "Stanford bunny" from a NOFF 3D model:

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Import and count the polygons stored in this file:

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Generate a 3D object using SphericalPlot3D and export it to NOFF:

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An Export example using inline 3D graphics:

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Introduced in 2007
(6.0)