An apparatus and method for displaying an operational area to an operative of a host platform, said operational area being defined within an external real-world environment relative to said host platform, the apparatus comprising a viewing device (12) configured to provide to said operative, in use, a three-dimensional view of said external real-world environment, a display generating device for creating images at the viewing device, and a processor (32) comprising an input (34) for receiving real-time first data representative of a specified target and its location within said external real-world environment and configured to receive or obtain second data representative of at least one characteristic of said specified target, the processor (32) being further configured to: use said first and second data to calculate a geometric volume representative of a region of influence of said specified target relative to said real-world external environment and/or said host platform, generate three-dimensional image data representative of said geometric volume, and display a three dimensional model, depicting said geometric volume and created using said three-dimensional image data, on said display generating device for creating images at the viewing device, the apparatus being configured to project or blend said three-dimensional model within said view of said external real-world environment at the relative location therein of said specified target.