Range images with triangulation
			
                          Pavel Krsek

                 Center for Machine Perception
                  Czech Technical University
               Faculty of Electrical Enginnering
                   krsek@vison.felk.cvut.cz
                   http://cmp.felk.cvut.cz

This file and the data files can be obtained via ftp:

 ftp://cmp.felk.cvut.cz/pub/cmp/data/range/polyhedra/o1/export        

This description of range data consists of two files. Coordinates of
vertices are stored in a file with extension .vtx and their
triangulation is stored in a file with extension .tri as indices of
the vertices. These two files are ASCII file with standard C++ number
notation.

Vertices: 

.vtx file is an ASCII file where each line corresponds to one point in
range image. There are 3 columns in each line. The X coordinates are
stored in column 1, Y coordinates are stored in column 2 and Z
coordinates are in column 3. The columns are delimited by SPACE (20h)
and lines are delimited by NEW_LINE (0Ah). The coordinates are in real
millimeters with two decimal numbers. The extension of file of
vertices is ".vtx".


Triangulation:

.tri file is an ASCII file too. Each line describes one triangle which
is defined on the vertices. The triangle is stored as 3 indices of
vertices. Therefore the each line has 3 columns (3 indices).  The
index is the number of line in vertices file. The line stores the 3D
coordinates of the vertex of the triangle.  The first vertex in .vtx
file has index 1. The negative and zero indexes are not used. The
columns are delimited by SPACE (20h) and lines are delimited by
NEW_LINE (0Ah). The extension of triangulation file is ".tri".


Example:

Let's have four vertices V1=(X1,Y1,Z1), V2=(X2,Y2,Z2), V3=(X3,Y3,Z3)
with the folowing triangulation:

  V1 --- V4
   |   / |
   |  /  |
   | /   |
  V2 --- V3

The information will be stored in the files:

Example.vtx:           
X1 Y1 Z1               
X2 Y2 Z2                
X3 Y3 Z3
X4 Y4 Z4

Example.tri:
1 2 4
2 3 4

NOTE: The sequence of indices in one line of triangulation file is
not guaranteed.