Autocad 2015 Portable Here

The answer is . Autodesk transitioned to a subscription model (SaaS) precisely to eliminate portability. Their business model relies on:

You do not need to download risky files to use CAD software portably. Autodesk and other developers offer safe, legal options. Autocad 2015 Portable

: A new way to select objects by drawing a freeform "lasso" around them. The answer is

Instead of risking your hardware and data with unofficial software, Autodesk provides legitimate tools for "portable" CAD work: Autocad 2015 Portable