Posts: 5

IGES to SAT conversion missing faces



Converting IGES file to SAT result in different results for R21 and R25. In R21 are missing faces.

The reason is that Subordinate flag for entity type 108 is 3 even if there are not physically dependent

parent for this entity 108. For me IGES data are invalid and conversion in R21 is right.

The question is why R25 can convert these entities? In R25 when parents are not found the flag is modified?

Or is there any new option in R25 that control this functionality?

Our user using R21 want to have the result in R25, is it possible by setting some option in R21?



gen1.igs is an input IGES file and ZIP file contains results for R21 and R25 using connect sample program

in default settings.





Spatial Employee
Posts: 22

Re: IGES to SAT conversion missing faces

We often get reports for IGES files that have entities that the user is expecting to see translated but strictly have the dependency flag set and have no parents.  Recently some logic was added to improve some cases and this is what you have noticed in R25.  As you mention the IGES data is actually invalid so if you want the strict interpretation you can control it with the option TranslateOnlyRootEntities.


The IGES Reader tries to identify the actual status of the entity (that is, whether it is Physically dependent, Logically dependent, Physical and Logical both dependency, or Independent), and depending on the actual status, it translates that entity.


This link provides the documentation: