When opening CATIA V5 files (.CATpart and .CATproduct), please note:
A CATIA V4 part referenced by a CATIA V5 part will not be loaded.
Non-manifold models are not supported.
Files with non-ASCII characters in their name or path cannot be loaded.
Note that there is also a loader for CATIA V4 files - see CATIA V4 Loader.