***************************************************************************
*
*    README_IGES
*    ===========
*
*    This README_IGES-file includes information about IGES import modules.
*
*    (C)rebro University   http://www.oru.se/tech/cad
*       Mohamed Rahayem     2006-10-25
***************************************************************************

1- The Authors :

 - Johan Kjellander  1997-12-22  johan.kjellander@tech.oru.se
 - Roy Kastelein     2000-04-12  r.e.f.kastelein@kastalyse.nl 
 - Sren Larsson     2006-09-06  soren.larsson@tech.oru.se
 - Mohamed Rahayem   2006-09-06  mohamed.rahayem@tech.oru.se  
 - Gunnar Liden      2000-06-02  Gunnar.Liden@phonak.com

2- Supported IGES entities:
  ___________________________________________________________
 |Entity No.| Entity Descrition                  |MBS Code   |
 |__________|____________________________________|___________|
 |  0       | Null Entity                        |  igs_0    |
 | 100      | Circular Arc Entity                |  igs_100  |
 | 104      | Conic Arc Entity                   |  igs_104  |             
 | 106      | Copious Data Entity                |  igs_106  |     
 | 102      | Composite Curve Entity             |  igs_102  |
 | 110      | Line Entity                        |  igs_110  |
 | 112      | Parametric Spline Curve Entity     |  igs_112  |
 | 116      | Point Entity                       |  igs_116  |
 | 120      | Surface of Revolution Entity       |  igs_120  |
 | 122      | Tabulated Cylinder Entity          |  igs_122  |
 | 124      | Transformation Matrix Entity       |  igs_124  |
 | 128      | Rational B_spline Surface Entity   |  igs_128  |
 |__________|____________________________________|___________|

3- IGES entities under development:
  ________________________________________________________________________________________________
 |Entity No.| Entity Descrition                  |MBS Code   | Status                             |
 |__________|____________________________________|___________|____________________________________|
 | 108      | Plane Entity                       |  igs_108  | need to support trimmed surface.   |
 | 118      | Ruled Surface Entity               |  igs_118  | not support yet.                   |
 | 126      | Rational B_spline Curve Entity     |  igs_126  | need to remove curve approximatiom.| 
 | 142      | Curve On parametric Surface Entity |  1gs_142  | under development.                 |
 | 144      | Trimmed(Parametric) Surface Entity |  igs_144  | under development.                 |
 |__________|____________________________________|___________|____________________________________|

3- To use level,color and blank attributes from the IGES-file you
   have to set the three parameters for igs_in to "Y",otherwise the 
   current attributes will be used. 
   Color numbers in IGES will map to pen numbers in Varkon.
   Blanked entities will be listed in the log-file.
   
4- Color definition entity (type 314) is not implemented. 
   That means: if an entity point to a color definition instead 
   of to a colour number, varkon will ignore this and use 
   the current pen number. 

5- Iges import files had been tested by using some existing iges 
   files downloaded from:
   http://iges5x.org/cals/.             
