Electrical and Mechanical Design Incremental Data Exchange Best Practice

The exchange of electrical and mechanical CAD data has had many import-export formats,
such as, DXF, and IDF. Each format has maintained a set of standards accepted by the CAD
industry. These formats have served well over the years, with one common underlying issue,
the exchange of data is considered, “all or nothing”. If a board outline, constraint areas, and
component placement is used initially, all the same data is continually exchanged
bidirectionally, even if just one object is modified. This exchange format makes it difficult to
manage design impact and track changes.

The EDMD schema, a new XML based data exchange format, was created to aid in the
exchange of ECAD-MCAD data by introducing the concept of passing incremental changes.
This implies that both the ECAD and MCAD tools begin at the same starting point, or
baseline, and any change from the baseline line is considered an incremental modification of
the data. The incremental data is then passed from one CAD tool to the other, not the entire
CAD interface data set.

Additional capabilities in the EDMD schema — commonly referred to as Incremental Data
Exchange (IDX) format — enhances the ability of design collaboration. The options provided
in the EDMD schema, such as ability to add comments, and accept or reject modifications,
improve communication between the two design disciplines. For example, after the design is
baselined, the PCB Designer may wish to move a component whose location was defined in
the baseline, the designer would export this change, and through a GUI, add a comment
describing the reason for the modification. The Mechanical Designer would preview the
incremental data, accept the change and import the data, or reject the change, and reply with
a comment explaining the reason for rejection, along with a possible new