BYU Files
Movie.BYU surface geometry files

BYU is a data directory which contains some examples of BYU files. More specifically, we are interested in Movie.BYU surface geometry files.

A Movie.BYU surface geometry file contains 4 groups of data.

The first group of data is a single line, containing 4 integers, each one left justified in 8 columns. The integers are:

PART_NUM, VERTEX_NUM, POLY_NUM, EDGE_NUM,
that is, the number of parts or objects, the number of vertices or nodes, the number of polygons or faces, and the number of edges.

The second group of data is a single line, containing 2 integers, each one left justified in 8 columnes. The integers are:

POLY1, POLY2,
the starting and ending polygon numbers. Presumably, this means that the polygons are labeled POLY1, POLY1+1, ..., POLY2, comprising a total of POLY_NUM polygons.

The third group is the X, Y and Z coordinates of all the vertices. These may be written using a FORTRAN format of 6E12.5, which crams two sets of (X,Y,Z) data onto each line, with each real value written in an exponential format with 5 places after the decimal. However, it is generally possible to write the XYZ coordinate data for each vertex on a separate line.

The fourth group defines the polygons in terms of the vertex indices. For each polygon, the vertices that make up the polygon are listed in counterclockwise order. The last vertex listed is given with a negative sign to indicate the end of the list. All the vertices for all the polygons are listed one after the other, using a format that puts up to 10 left-justified integers on a line, with each integer occupying 8 spaces.

Example of a BYU file: 

           1       8       6      24
           1       6
     0.00000E+00 0.00000E+00 0.00000E+00
     1.00000E+00 0.00000E+00 0.00000E+00
     1.00000E+00 2.00000E+00 0.00000E+00
     0.00000E+00 2.00000E+00 0.00000E+00
     0.00000E+00 0.00000E+00 1.00000E+00
     1.00000E+00 0.00000E+00 1.00000E+00
     1.00000E+00 2.00000E+00 1.00000E+00
     0.00000E+00 2.00000E+00 1.00000E+00
           4       3       2      -1
           5       6       7      -8
           1       5       8      -4
           4       8       7      -3
           3       7       6      -2
           2       6       5      -1

BYU File Characteristics:

Licensing:

The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.

Sample files:

You can go up one level to the DATA page.

Last revised on 15 September 2004.