Getting back to our car analogy, now that the engine, steering, and brakes work, Autodesk is adding the seats, doors, windshield, and windshield wipers. But before we get into the new features, let's review the existing basics. First, although it uses the industry-standard ACIS solid modeling kernel, it stores file data. Virtually all CAD programs store data chronologically in the order you create it. When a program opens a file, it reads it from beginning to end, then sorts the data into graphic and numeric categories.
Inventor sorts the data before it saves it to disk.
All the graphic information goes first, followed by the numerical. When Inventor opens a file, it finds all the graphic information at the front of the file and so tosses up the screen picture very quickly. As you begin working, it retrieves numerical information as needed. The net result is that assembly drawings containing several thousand parts open within a few seconds rather than the usual tenplus minutes. Inventor's other unique feature is its adaptive assemblies.