The most optimum approach would be to export the part or assembly from Fusion as .STP then import it into Inventor. This would not only give you excellent layout of individual assembly parts in Inventor, but will also allow you to manipulate various parts' features in Inventor using direct edit.STP or STEP file (ISO 10303-21) is the best format for transferring files across platforms as it is not only compatible with almost all 3D design softwares out there, it is also very compact. Most of the time, I am able to save more than 40% of the original design file by exporting it in STEP format. Additionally, STEP files handle compression with great efficiency, thus from the original CAD file you can go down in size by almost 90% using STP + compression (using ordinary .ZIP compression).For more about STEP format, formalized in 1994, check Wikipedia: http://en.wikipedia.org/wiki/ISO...