DeMille's granddaughter Cecilia DeMille Presley remembers going into C.B.'s office during production of Unconquered; "...there wasn't a spot to sit down... the room was filled with the exciting, vibrant dramatic, compelling sketches and scene paintings of Dan Groesbeck."
DeMille was one of the first directors to hire a visualisation artist, a practice he regarded as indispensable. DeMille himself explained, "In 1926 I was already beginning the practice, which is invariable with me now, of having on my production staff one or more artists to make sketches of every scene, every shot, every costume, every important prop... it completely eliminates the misunderstandings which can arise when one depends upon words alone for the description of anything... [Groesbeck] always knew what I wanted and he could capture character and drama in a few strokes of his brush." DeMille found Groesbeck's characters so powerful, he cast with their features in mind.
According to former art director Herbert Ryman, Groesbeck's sketches were "an inspiration to the creativity of the director and cameraman." Robert Henning tells us that, through the extensive representation of his works in the collections of Brigham Young University and the DeMille Foundation, "it is clear that Groesbeck made a major contribution to the casting, costuming, dramatic action, and overall atmosphere of more than twenty films." Presley believes that "Groesbeck's chief asset to a DeMille picture was his unique ability to understand DeMille's point of view - and then get it down on paper," or as John Kobal says, having Groesbeck was like having an artist on call "to visualise his dreams."