1. A product lifecycle management system, comprising: a database storing modeled objects and relations between said objects; and a graphical user interface suitable for displaying to a user a graphical representation of a hierarchy of modeled objects stored in said database; wherein the graphical user interface is adapted, upon selection of a displayed object from said modeled objects by a user, to display modeled objects stored in said database related to the selected object; wherein, at a given level in the hierarchy, displayed modeled objects are distributed according to a respective weight; and wherein the weight of a displayed object depends on the number of descendants of said object in the hierarchy which are displayed in said graphical representation.