Indeed, when I have the option of making the hull shape myself, such as for the sample files I sent, I can simply export the surface objects themselves and load the resulting IGES into NAPA without problems.
However, I often have to work with geometry that has been provided by another party in a different format, such as a Parasolid. Where NAPA cannot read Parasolid files, CAESES can. Therefore, I was attempting to use CAESES to convert the Parasolid file into a format which NAPA can read, the most feasible of which was an IGES file. As Parasolid files are imported into CAESES as Brep objects, this lead to my initial question.
In any case, thank you for your help, and I will contact NAPA support to see if they can do anything about their IGES interpreter. If you have any other ideas on how to handle this type of process, I am open to suggestions .