Mathematica Import/Export Format

PLY (.ply)

3D geometry format.
ASCII or binary format.
Used for storage and interchange of 3D graphical objects.
Known as Stanford Triangle Format.
PLY is an acronym derived from polygon.
Stores a 3D object as a collection of line and polygon primitives and their properties.
Allows user-defined format elements.

Import and Export fully support the ASCII and binary PLY file formats.

IMPORT AND EXPORT

Import["file.ply"]imports a PLY file as a Graphics3D object.

Export["file.ply", expr] exports a Graphics3D expression to a binary PLY file.

Import["file.ply"] returns an expression of the form Graphics3D[ GraphicsComplex[vertices, primitives, opts]].

Import["file.ply", elem] imports the specified element from a PLY file.

Import["file.ply", {elem, sub_a, sub_b, ...}] imports a subelement.

Import["file.ply", {{elem₁, elem₂, ...}}] imports multiple elements.

The import format can be specified with Import["file","PLY"] or Import["file", {"PLY", elem, ...}].

Export["file.ply", expr, elem] creates a binary PLY file by treating expr as specifying element elem.

Export["file.ply", {expr₁, expr₂, ...}, {{elem₁, elem₂, ...}}] treats each expr_i as specifying the corresponding elem_i.

Export["file.ply", expr, opt₁->val₁, ...] exports expr with the specified option elements taken to have the specified values.

Export["file.ply", {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 PLY format.

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:

	"Graphics3D"	PLY file represented as a Graphics3D object
	"GraphicsComplex"	PLY file as a GraphicsComplex object
	"LineData"	the line elements of a PLY file in indexed form, with integer indices referencing the vertices as given by "VertexData"
	"LineObjects"	list of Line primitives given in absolute coordinates
	"PolygonData"	the polygon elements in indexed form
	"PolygonObjects"	list of Polygon primitives given in absolute coordinates
	"UserExtensions"	user-defined data associated with polygon vertices
	"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 use the "Graphics3D" element by default for PLY files.

The "VertexData" element corresponds to the first argument of GraphicsComplex.

When rendering a PLY color model, Import automatically uses the setting Lighting->"Neutral".

User-defined elements:

	"UserExtensions"	names of user-defined data fields, given as a list of strings
	"UserExtensions",field	user-defined data field as a list of values associated to each vertex as given by "VertexData"

OPTIONS

General Import options:

Background	Automatic	what background color to use
ImageSize	Automatic	overall size of the graphics to display
Lighting	Automatic	what simulated lighting to use in coloring 3D surfaces

Advanced options:

"BinaryFormat"	True	whether the file is in ASCII or binary format
"DataFormat"	Automatic	data types used in the binary format
"InvertNormals"	False	whether to invert the orientation of vertex normals
"VerticalAxis"	{0,0,1}	orientation to assume for the coordinate system used in the file

Binary PLY files normally store data as IEEE single-precision floating-point numbers, which correspond to the setting "DataFormat"->"Real32".

With the setting "DataFormat"->"Real34", vertices and normal vectors are stored as double-precision numbers.

The data types used for the vertex coordinates and for the normal vectors can be specified explicitly with "DataFormat" -> {vtype, ntype} or "DataFormat"-> {{vtype_x, vtype_y, vtype_z}, {ntype_x, ntype_y, ntype_z}}.

By default, Mathematica assumes that in the coordinate system used by the PLY format the vertical axis corresponds to the third coordinate.

With the setting "VerticalAxis"->{0, 1, 0}, Mathematica will apply the transformation {x, y, z}->{x, -z, y} to all graphics coordinates when importing from PLY, and the inverse transformation when exporting to PLY.