1. A man-machine interface method for permitting a user to act on thumbnails, each thumbnail representing an associated object containing information, for use with a machine having a video display device and a user input device, the man-machine interface method comprising: generating a three-dimensional environment to be rendered on the video display device, the three-dimensional environment comprising an object manipulation and display field having surfaces including a bottom, a transparent front wall, a rear wall and side walls; determining a two-dimensional location and a depth of each of the thumbnails in the three-dimensional environment, wherein, for each of the thumbnails: the depth is a function of at least one parameter of the object associated with the thumbnail; and the two-dimensional location and the depth is determined that prevents total occlusion of the thumbnail by one or more other of the thumbnails in the three-dimensional environment; generating the thumbnails within the three-dimensional environment, at the determined two-dimensional locations and depths, to be rendered on the video display device; accepting inputs from the user input device; determining a selected viewing point, two-dimensional location, depth and direction based on the accepted inputs; and generating, as visible, a portion of the three-dimensional environment and those thumbnails that are in front of the selected viewing point to be rendered on the video display device, wherein those thumbnails that are in back of the selected viewing point are not visible and cast corresponding shadows on the at least one of the surfaces.