 According to Bagdasarian Jr., getting the look of the chipmunks suited for a live-action setting while maintaining the essence of the cartoon designs was challenging, and it took until September 10, 2006 for the artists to get it right.Hill instructed the artists to make the chipmunks look realistic, but not entirely like chipmunks.In addition to observing real chipmunks offered by Universal Studios, Rhythm and Hues studied all versions of the chipmunk characters from past "Alvin" media for conceiving, fur-texturing, and animating designs for the film.