Object File Format

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Object File Format
File extension : .off .coff .noff .cnoff
Magic number : OFF
Type: ASCII format
Container for: 3D models


Format for of 3D and 2D textures

Object file format called a very simple data format , the one from any polygons composite polyhedron describes and is used by scientific programs with 2D manifolds in 3D work. The surfaces in these 3D models are described with unstructured triangular grids. The name extension for these files is typically .off.

construction

A file in the Object File Format is a text file in ASCII coding. All numerical values are spaces separated when decimal separator is a point .

The first line of the file consists only of the keyword OFF . The second line contains three natural numbers for the number of vertices , faces and edges of the polyhedron. The number of edges can be ignored by processing programs, since this is clearly determined by the number of corners and surfaces .

The following lines each describe a corner point using its three Cartesian coordinates x, y and z. The individual corner points are not explicitly indexed , the points are implicitly numbered from zero according to their order.

The list of the corner points is followed by a line for each area. First, the number of corner points of the surface is specified and then the indices of the corner points are listed, thus defining a triangle strip .

Optionally, the triangular grid can be provided with colors.

example

OFF
# cuboid.off
# Ein Quader.

8 6 12
 1.0   0.0   1.0
 0.0   1.0   1.0
-1.0   0.0   1.0
 0.0  -1.0   1.0
 1.0   0.0  -1.0
 0.0   1.0  -1.0
-1.0   0.0  -1.0
 0.0  -1.0  -1.0
 4  0 1 2 3
 4  7 4 0 3
 4  4 5 1 0
 4  5 6 2 1
 4  3 2 6 7
 4  6 5 4 7

More examples can be found on the Princeton Benchmark for 3D Mesh Segmentation website .

Related file formats

Web links

Individual evidence

  1. ↑ OFF - Geomview Manual. Retrieved November 27, 2019 .
  2. ↑ Xiaobai Chen and Aleksey Golovinskiy and Thomas Funkhouser: A Benchmark for 3D Mesh Segmentation . In: ACM Transactions on Graphics (Proc. SIGGRAPH ) . tape 28 , no. 3 , 2009.
  3. ↑ A Benchmark for 3D Mesh Segmentation. Retrieved November 27, 2019 .