1. A method for navigating in a product structure of a product, the product comprising a set of three-dimensional modeled objects, the method comprising: displaying three-dimensional graphical representations of each three-dimensional modeled object forming the product; selecting a three-dimensional modeled object of the product among the three-dimensional modeled objects graphically represented; determining a number of levels of a hierarchy of the product structure of the product, the number of levels being determined according to levels identified in a simple path in the hierarchy of the product structure between the selected three-dimensional modeled object and a highest level of the hierarchy; displaying a graphical representation of the number of levels determined of the hierarchy of the product structure of the product; selecting, on the graphical representation of the number of levels, the number of levels being from the simple path in the hierarchy of the product structure between the selected three-dimensional modeled object and the highest level of the hierarchy, a level among levels identified in the simple path in the hierarchy of the product structure of the product; finding, in the set of three-dimensional modeled objects, a second set of three-dimensional modeled objects according to the selected level of the hierarchy, the second set comprising the three-dimensional modeled objects of a subtree of the selected level of the hierarchy, the subtree comprising the selected level of the hierarchy and descendants of the selected level of the hierarchy; and emphasizing the display of the found second set of three-dimensional modeled objects.