IGES Import/Export FAQ

1. Which IGES versions/subsets can be used with MicroStation?
2. What is a .LOG file?
3. Where can I find the .LOG file that was generated by the IGES translator?
4. Why do I receive "low on virtual memory" messages while translating?
5. Can I customize my IGES translations?
6. How can I ensure that the .IGS file I am trying to import into MicroStation is correct?
7. I imported an IGES file and it completed, but nothing is in my .DGN file.
8. I imported an IGES file and it completed, but some entities are missing.
9. After I import an IGES file completely, the 'Fit All' command compresses my drawing into one dot.
10. After I import an IGES file completely, the lines are too thick.
11. I exported my .DGN file into IGES completely, but the receiving system does not support certain entities, such as trimmed surface boundaries, in my IGES file.

Question 1: Which IGES versions/subsets can be used with MicroStation?

Answer: The following versions/subsets can be used:

• MicroStation imports files from IGES versions 3.0 to 5.0 and exports files to IGES version 4.0 or 5.0
• MicroStation supports the VDA-IS, CALS 1 and 2, and JAMA-IS 1.04 subsets

Starting in Q1 1998, MicroStation will import/export IGES version 5.3 files.

Question 2: What is a .LOG file?

Answer: The MicroStation IGES translator creates a log file, which is a text file to allow users to view statistics and diagnostics (the messages that display during translation). This should be the first resource used for trouble shooting.

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Question 3: Where can I find the .LOG file that was generated by the IGES translator?

Answer: By default, the log file will be in the ..\ustation\out\iges directory and have the same filename as the translated file, but with a .LOG extension. Users can specify the log file name and path by choosing File > Log File in the IGES Import or IGES Export dialog box.

Question 4: Why do I receive "low on virtual memory" messages while translating?

Answer: Depending upon your system parameters, some IGES translations will require significant amounts of virtual memory. You can increase the virtual memory settings on your system to provide more resources. Ideally, you should create a permanent swap file by setting your Initial and Maximum values to be equal.

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Question 5: Can I customize my IGES translations?

Answer: Yes. The MicroStation IGES translator can be easily customized through the dialog box settings. For example, users can map fonts and line styles as well as control which IGES/MicroStation entities are translated. This requires a substantial knowledge of IGES. Please refer to "IGES File Exchange" in Chapter 6 of the MicroStation 95 Administrator's Guide for details.

Question 6: How can I ensure that the .IGS file I am trying to import into MicroStation is correct?

Answer: Use an IGES verification utility such as IGES Parser-Verifier from IDA (http://www.idacorp.com) or IGES/Works from ITI (http://www.iti-oh.com).

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Question 7: I imported an IGES file and it completed, but nothing is in my .DGN file.

Answer: The IGES file probably has a 'drawing entity' (type 404) defined and the rest of the elements are marked as belonging to that drawing. By default, these entities are placed into a separate sheet file. Check for sheet files, which will have the same filename as the design (.DGN) file with a .SHT extension.

If the file is from a recent version of Unigraphics, SELECT subscribers can receive an updated MicroStation IGES translator from Bentley Support (see the end of this FAQ for Support contact information). This update has been enhanced to handle changes in the Unigraphics IGES translator. To use the updated MicroStation IGES translator, place the new IGESIN.MA file in the ..\ustation\mdlsys\asneeded\ directory. In the Import IGES dialog, choose Settings > General and set Drawings to Sheet - View Visibility.

Less likely is that the file contains no entities the MicroStation IGES translator supports. About the only possibility for this would be type 143 (new trimmed surface). We do support the commonly used type 144 entity (trimmed surface). Check the log file for 'unsupported entity' messages.

Question 8: I imported an IGES file and it completed, but some entities are missing.

Answer: After checking for situations described in Question 7, the most likely candidate is a trimmed surface which is in some way defective. Check the log file for a 'missing uv_curve' or 'uv_curve not closed' message. The latest MicroStation IGES translator, available to SELECT subscribers from Bentley Support, has improved its handling of these situations (see the end of this FAQ for Support contact information).

If you receive an 'unsupported b-spline order' message, then the b-spline surface/curve in the IGES file has an order greater than 15, which is the MicroStation limit. We are currently working on this issue, so please notify support of this error and supply the problem file (see the end of this FAQ for Support contact information).

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Question 9: After I import an IGES file completely, the 'Fit All' command compresses my drawing into one dot.

Answer: This is typically caused by a bad entity in the file - for example, a line that goes into infinity. Delete all entities which seem to be out of place.

Question 10: After I import an IGES file completely, the lines are too thick.

Answer: Older versions of the MicroStation IGES translator set line weights incorrectly when the IGES file global section had zero max line width, but non-zero number of line weight gradations. To resolve the issue, use the Change Element Attributes command or SELECT subscribers may get the latest MicroStation IGES translator from Bentley Support (see the end of this FAQ for Support contact information).

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Question 11: I exported my .DGN file into IGES completely, but the receiving system does not support certain entities, such as trimmed surface boundaries, in my IGES file.

Answer: You can control the output by choosing Settings > Exclude IGES Entities in the IGES Export dialog box. MicroStation design files store and export a trim boundary as a polyline. When a MicroStation Modeler feature is exported, the underlying ACIS structure is used, which produces an exact curve. However, importing a trimmed surface into MicroStation Modeler will result in a MicroStation trimmed surface with a polyline boundary. Please refer to "IGES File Exchange" in Chapter 6 of the MicroStation 95 Administrator's Guide for details.