A synthetic scene of real-word objects is obtained through the multiplexing of several digital holograms. Moreover, by an opportune numerical hologram deformation, it is possible to synthesize 3D dynamic scenes that can be displayed by means of a spatial light modulator. In fact, the spatial adaptive deformation of digital holograms allows the control of the object position and size in a 3D volume with a high depth of focus. Through this novel technique a 3D dynamic scenes can be projected as an alternative to difficult and heavy computations needed to generate realistic-looking computer generated holograms. Finally we report the result of a pilot experiment to evaluate how viewers perceive depth in a conventional single-view display of these dynamic 3D scenes.