This paper by Cyon Research argues that successful interoperability projects first require an understanding of the ultimate use of the data. They also require the use of capable software tools, sophisticated processes, careful validation, and, guidance from people with expertise and experience in interoperability. Interoperability is not a one-size-fits-all proposition. There are many common use scenarios which require that the product data be treated differently. There are also significant interoperability challenges, including continuing difficulties in translating basic geometric and topological information, complexities in translating semantic information, lack of information on common file formats, limited information content in some file formats, and uncertainty about the needs of the ultimate data user. These challenges can be better addressed by understanding the data.