NAS or large file solutions

My approach on this for customers i work with in an engineering or media production space is as Dean advised. As these files are being worked on, syncing them provides little benefit as you cant collaborate together on the files as the application doesn't support partial file updates like office does. Mapping a drive is not a good idea as it looses the authentication token each day and won't will get issues with multiple people opening the same file as users will overwrite each others work.
In most cases the need to store CAD and media in SharePoint is to publish for review or approval or review in a PDF or other suitable format.