AVS Modules                                                      draw polygon

NAME
     draw polygon - draw a polyhedron object from user specified polygons

SUMMARY
     Name	   draw polygon

     Type	   data input

     Author        Anonymous g69d

     Inputs	   none 

     Outputs	   geometry 

     Parameters	   Name		   Type
		   data file	   browser

DESCRIPTION
     This module reads an ascii input file and creates a set of polygons
     in a single geometry object.  The module expects the file to have
     an extention of ".ply" or ".txt". 

     Polygons can have different numbers of vertices.  The information that
     must be supplied in the ascii file is the number of polygons, the 
     number of vertices in each polygon, and the coordinate information for
     the vertices.  Additionally, normal information may be supplied for 
     each polygon.  In this module, it is assumed that the  polygons are 
     flat, and therefore only require 1 normal per polygon, instead of one
     per vertex.  If the normal information is not present, the vertices are
     assumed to be arranged counterclockwise from the "outside" viewpoint.

INPUTS
     none

OUTPUTS
     a geometry containing a poly-line object is output

PARAMETERS
     data file		-the name of the ascii file with the list of points
			 for the line segments.  File format is as follows:

  <number_of_polygons> <Max_num_of_vertices_per_polygon> <normals_present?>
  <number_of_vertexes_in_polygon_1>
  <vertex1_poly1x> <vertex1_poly1y> <vertex1_poly1z>
  <vertex2_poly1x> ...
  .
  .
  <normal_poly1x> <normal_poly1y> <normal_poly1z>
  <number_of_vertexes_in_polygon_2>
  <vertex1_poly2x> <vertex1_poly2y> <vertex1_poly2z>
  <vertex2_poly2x> ...
  .
  .
  <EOF>

  The <normals_present?> is a boolean flag indicating whether or not the
  normal information lines exist in the files.


EXAMPLE
     Typical network usage:

     lines to geom
	       |
     geometry viewer