Creating a design sketch from plain paper to digital rendering takes a long time, but AMG has condensed the process for us to show what's involved.
In this time-lapse video an AMG designer starts with a hand drawn sketch which is scanned and loaded into photo editing software - in this case Photoshop CS5. From here, the artist uses a digital sketch pad to add color and the finishing touches.
Just a quick note: At 0:26 in the video don't be fooled when the artist holds the paper sketch up to the monitor and it magically appears on screen. This isn't some secret technology but most likely shown this way for editing purposes.