One method is to set up a bank of digital cameras around the subject along the route of the virtual camera pan. At the appropriate point all of these cameras take a photo and these images are used as master frames. A computer is the used to interpolate between the image coordinates to create additional image frames. This set of real and interpolated images are then stitched together to create the film. This was the technique used in the filming of The Matrix and considerably since - see the documentary of The Matrix for a more detailed explanation.