3D IGES: FAQ

Here is a non-exhaustive list of Frequently Asked Questions about the IGES export and import process.
The most common problems are gathered here to help trouble-shooting. 

Import

 
  • Question :
    the application cannot open the IGES file and returns an "invalid input file" error message, what can I do?
  • Answer :
    As the error message suggests , the IGES file is indeed a poor quality IGES file that cannot be opened. 
    The best thing to do is to contact the provider of the IGES file and ask for a more decent file.

 
 
  • Question: 
    The application crashes when I open the IGES file with a "Run Time Exception", why ?
  • Answer :
    It is obviously a bug that was not fixed on the release you are using.
    If you do not use the latest release, you can consider upgrading or contact your local support.
 
  • Question :
    I get a 'Low memory state' warning message and my IGES file is not totally converted.
  • Answer :
    there is not enough memory to convert the file completely and all the remaining entities are skipped.
    We recommend to use Windows NT4SP06 (and above) for big IGES files and use
  • at least 1 GB of RAM and 2 GB of SWAP.
 

  • Question :
    I  opened my IGES file successfully but I have some KO faces that were moved to the NoShow section,
    what was wrong?

  • Answer :
    there could be many reasons why KO faces are returned but it is usually due to the fact
    that it  was not possible to recreate the geometry contained in the IGES file.
    To avoid those KO faces, you can try and import the IGES using a different import option for
    Representation for boundaries of trimmed and bounded surfaces. 
    If you still have KO faces, you may consider repairing those faces using the
    methodology described in the chapter 3D IGES: Trouble Shooting
 

  • Question :
    all the dimensions of my IGES file were multiplied by 25.4, why ?

  • Answer :
    the most common cause for this problem is a problem in the header of the IGES file which is not correct.
    Therefore,  the application can not read correctly the dimension system used by the user and takes
    the 'inch' as the default system. That explains why all the dimensions are multiplied by 25.4.
    Then you can either modify manually the IGES file to repair it or you can ask the provider of the IGES file
    to provide a good quality file
 
 
  • Question :
    I have a KO Face: in the KO-Body, I have only Surfaces (no curve); in the .err file, I can read.
     
    How can I repair my face ?
  Answer:
The Surface must be a C2 B-Spline. The reason of the problem is that there is not the 3D-representation for
the curves in the IGES File.
The Face type is 144. The Boundary type is 142. This Boundary should reference two Curves Representations :
  • First, a 2D-Parametric Curves Representation: OK, in our case.
  • Then, a 3D Curves Representation: Missing in our case!

CATIA V5 only uses the 2D representation if the B-Spline Surface is C2-continuous.
Here, the B-Spline Surface is not C2. CATIA V5 must cut it in C2 Surfaces and cannot use the 2D Curves Representation.
With Continuity Optimization of Curves and Surfaces option, B-Spline Surfaces are approximated to be
C2-continuous and 2D curves can be used (B-Spline Surfaces are C2).
All Faces are OK !

 
  • Question :
    Even with correct IGES Options, I still have a KO Face :
    n the KO-Body, I have only one not-cut B-Spline Surface (no curve);
    in the .err file, I can read There is no 3D curve....
    How can I repair my face ?
 
  • Answer:
    The IGES File is invalid and has 2 problems:
    • First, There is NO 3D Curves Representation.
    • and the 2D Curves Representation is incorrect :

    For the 2D Curves, the Entity Use Flag, in the Status Number, should be "05" for "2D-Parametric". 
    In the IGES File, this flag is "00", which means 3D Curves! Replace the incorrect flag "00" by "05"
    for all 2D Curves in the IGES file. 

Export

  • Question :
    When examining my .rpt file, I see I have some KO faces , what should I do?

  • Answer :
    KO faces when exporting may be caused by a corrupted CATPart.
    You can try and use the CATDUA utility to see if there is nothing to be done on the CATPart itself.
    If, despite all, you still get KO faces when exporting to IGES, please contact your local support.

  • Question :
    The IGES file created by my application is not correctly opened by my CAD package, what should I do?

  • Answer :
    You can try to use the export with the two available options for Curve and surface type :
    Standard and BSpline.
    The BSpline option may give better results with some CAD systems and the Standard option give
    better results with others. 
    If the result is still bad with the receiving system, you may want to investigate i
    f the CATPart is not corrupted and
    use the CATDUA program to upgrade the CATPart. Finally, if the result is still not the expected one,
    it could be a problem with the CAD receiver system itself.

  • Question :
    I am losing some parts of my assembly while exporting my CATProduct to IGES, why ?

  • Answer :
    Make sure that you do not have any foreign parts included in your CATProduct like STL files or Parasolid files...etc.
    Those files do not contain any V5 information except the visualization information and therefore it is impossible
    to export them as IGES file. If you have CATIA V4 .models in your CATProduct, make sure to have them migrated
    to V5 before exporting to IGES.