We have a problem with IfcMapConversion

Users
1

Hi all, we (the BIM industry) have a problem with IfcMapConversion. Or actually two problems:

  1. We’ve seen two examples recently of software that is writing IfcMapConversion incorrectly. Specifically, in both cases, projected map coordinates were used as model coordinates (which is valid), but an IfcMapConversion was also included, which makes the final coordinates wildly wrong.
  2. Very little software actually reads IfcMapConversion. Software that ignores the IfcMapConversion appears to give correct results when it reads one of these badly formed files, software that correctly applies the IfcMapConversion appears to give an incorrect result.
1 Like
2

IfcMapConversion is not that useful unless the combined scale factor is 1.0
IfcMapConversionScaled in IFC 4x3 is the correct one to us.

3

Please report the bugs to any software vendor that 1) writes it incorrectly or 2) does not read it correctly or ignores it. They might not be aware of the issue.