摘要：Today exchange of data among CAD systems becomes more important. As each CAD system has its own flavor to represent the same objects, exchange of data among them is full of issues. Most common problems are incomplete transfer of presentation information, associativity between representation and presentation, usage of annotation planes and text. They are analyzed in details and possible solutions are suggested as well.
关键词：Data exchange; STEP; data models; GD&T; presentation; representation
