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IDProjectCategoryView StatusLast Update
0027069CommunityOCCT:Data Exchangepublic2023-08-01 15:08
ReporterRoman Lygin Assigned Togka 
Status newResolutionopen 
Product Version6.9.1 
Target VersionUnscheduled 
Summary0027069: IGES parser does not recognize comments in Parameters section
DescriptionThe IGES parser is not able to recognize comments which are allowed by the IGES spec, issues false positive warnings, and populates IGES model with invalid data. As a result the IGES file cannot be converted afterwards.

This is a root-cause of issues reported at See also attached a simpler reproducer.

Excerpt from IGES spec 5.3:
" Any desired comment may be added after the record delimiter. Additional comment lines may be used by keeping the same Directory Entry pointer in Columns 65-72 and including the comment lines in the entity’s parameter line count (DE Field 14)."
Steps To Reproduceigesbrep points-with-comments.igs
data c
# must be no warnings/errors
Additional information
and documentation updates
Preliminary analysis shows that the IGES parser does not attempt to associate P section entries to D section entities using references from D to P. Instead it uses a consecutive list of parameters from the P section and just incrementally associates them to D entities. When the parser encounters a multi-line comment or a comment taking a new line in the P section it mistakenly interprets it as a string parameter what breaks this incremental association and thus further parsing.

No fix currently available.
TagsNo tags attached.
Test case numberbugs xde bug27069

Attached Files

  • points-with-comments.igs (1,394 bytes)


Roman Lygin

2016-01-09 21:33


points-with-comments.igs (1,394 bytes)


2017-08-17 14:36

tester   ~0069523

Problem described in issue is reproduced on current state of OCCT.

Issue History

Date Modified Username Field Change
2016-01-09 21:33 Roman Lygin New Issue
2016-01-09 21:33 Roman Lygin Assigned To => gka
2016-01-09 21:33 Roman Lygin File Added: points-with-comments.igs
2016-10-26 11:54 gka Target Version 7.1.0 => 7.2.0
2017-07-27 09:24 abv Target Version 7.2.0 => 7.4.0
2017-08-17 14:36 mkv Test case number => bugs xde bug27069
2017-08-17 14:36 mkv Note Added: 0069523
2019-09-04 13:04 abv Target Version 7.4.0 => 7.5.0
2020-09-11 18:46 gka Target Version 7.5.0 => 7.6.0
2021-10-18 14:02 kgv Target Version 7.6.0 => 7.7.0
2022-10-24 10:39 szy Target Version 7.7.0 => 7.8.0
2023-08-01 15:08 dpasukhi Target Version 7.8.0 => Unscheduled