Abstract: Visualizable data are obtained that represent a scene with at least one object. The visualizable data describe the scene as seen from a position. First and second measures are determined, which represent extensions of one of the objects in a smallest and a largest dimension respectively. An object aspect ratio is calculated that represents a relationship between the first and second measures. Based on the object aspect ratio, a selection margin is assigned to the object. The selection margin designates a zone outside of the object within which zone the object is validly selectable for manipulation in addition to an area of the object shown towards a view thereof as seen from the position. Thus, it is made easier to manipulatable the visualizable data in response to user input, for instance in the form of gaze-based selection commands.