Using an accepted industry standard, such as IGES and VDA-FS, to exchange geometric information between a CAD system and Abaqus/CAE is not a guarantee of success. When a CAD system exports a part, the system maps its proprietary representation of the part into an array of entities available from the standard. Similarly, when Abaqus/CAE imports the file, it converts the entities defined by the standard into its internal representation—ACIS.

ACIS recognizes only some of the entities defined in the IGES and VDA-FS standards and also expects a certain level of smoothness or continuity in the trimmed surfaces. Although the exporting CAD system is not aware of the requirements of Abaqus/CAE, setting the correct export options will increase your chance of success. For more information, see “How do solid modelers represent a solid?,” Section 10.1.7, and “Understanding the contents of an IGES file,” Section 10.4.

In addition, you may experience problems because CAD systems interpret the industry standards differently. In many cases there is more than one way to define a geometric entity, resulting in a particular “flavor” of the file format. In more extreme cases, vendors violate the standard, especially when creating trimmed surfaces.