"You don't LOSE compatibility with other software" I disagree, one of the complaints about Poser 5 was the loss of some import/export capabilities with some of the high end packages, which is why we now have to buy Body Studio. "but some features of Poser 5 are not compatible with other 3D packages." Off course, but then again, it could be said that some features of other 3D packages are not compatible with Poser 5. But that is true of all 3D packages, they will all have some propriety format that makes them unique and precludes total compatibility with others, which is why people have to develop plug-ins.