CAD tip # 10727:

If you are using a later Inventor release, you can scale a part (make it larger or smaller) not only by creating a derived part but also through direct editing. So you can easily scale also 3D parts imported from other CAD formats (STEP, IGES, etc.).

You can use the direct editing tool to change a part scale, and you can even use a independent scale in all X-Y-Z axes (Uniform/Non-uniform scale).