Because Bumblebee isn’t able to speak (his voice box was removed by a Decepticon ), Knight saw the eyes as the place where the character could be the most revealing. So they are larger and brighter and tell more of a story on their own than in the Michael Bay films. (Think Brad Bird’s animated fable “The Iron Giant” with a little “E.T.” mixed in.)

The mechanics of the character were streamlined as well, rounding his edges more and reducing the parts to fewer, but still transformable, segments.

“Instead of the upper arm being made out of 50 small pieces, it might be made out of three large panels supported by small parts,” said the visual effects supervisor, Jason Smith, of Industrial Light and Magic. He has worked on four “Transformers” films , beginning with the 2007 installment.

Did this simplification of the design make it easier for the artists? Not exactly.

“It’s not much of a savings in terms of effort,” Smith said. “Because when you replace these multiple pieces with a large panel, you have to make that panel really read as something physical and real.” So more effort is put into how the paint and the metal look and what it takes to make Bumblebee feel like he’s moving in more emotional ways.