I have a completed car model that I would like to modify. It consists of parts of the car as seperate objects. Ie, car body, bumper, windshield etc are seperate objects. In order to continue working on the car it would make sense to bisect each of these objects and mirror them with alt-d. However it would be nice if it were possible to cut every object in the set of objects composing the car instead of cutting every object by itself. Is this possible?
To do all objects in one go Join them together to form one object (Ctrl+J), cut in half and seperate them (P in edit mode)
Instead of Alt+D why not use the mirror modifier, You can clip and merge vertices along the centre line, required if you want to use any Subdivision surface modifier for objects that lie on the mirror plane