BYU geometry is described using verticies, connectivity, and parts. A vertex is a point location, and is specified by x, y and z coordinates. The order that the verticies appear in the file determines vertex indecies, with the first vertex being number one, the next vertex number two, and so forth. A polygon is specified as a list of vertecies. In the file format the last vertex index for each polygon is negated. A part is composed of a consecutive set of polygons, such as polygons 121 thru 233.
The geometry file has four sections. The first section is one line long, and specifies array dimensions. The second section describes the part boundaries. The third section contains x-y-z coordinates for all of the vertecies. The fourth section is the connectivity array, a list of vertex indecies that describe the polygons.
The first section contains four integers in the following order: the number of parts, the number vertecies, the number of polygons, and the number of entries in the connectivity array.
The next section contains two integers for every part: the starting polygon number and the ending polygon number.
The third section lists three floating point numbers for every vertex: the x, y and z coordinates.
The last section is a list of integers describing connectivity. For each polygon the vertex numbers are listed, with the last vertex negated.
The scalar file is simply a list of floating points numbers, one per vertex.
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 1.00000e+00 0.00000e+00 0.00000e+00 1.00000e+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 1.00000e+00 1.00000e+00 0.00000e+00 1.00000e+00 1.00000e+00 1 4 3 -2 5 6 7 -8 1 2 6 -5 2 3 7 -6 3 4 8 -7 4 1 5 -8
A sample scalar file for this cube:
0.00000e+00 1.00000e+00 2.00000e+00 3.00000e+00 4.00000e+00 5.00000e+00 6.00000e+00 7.00000e+00