Résumé : We show, in this paper, how one can compute the exact shapes of a class of polyhedral scenes by means of a simple sensory device issuing probes. A scene in this class consists of disjoint polyhedra with no collinear edges, no coplanar faces and such that no edge is contained in the supporting plane of a non incident face. The basic step of our method is a strategy for probing a single simple polygon with no collinear edges. When each probe outcome consists of a contact point and the normal to the object at the point, we present a strategy that allows to compute the exact shape of a simple polygon with no collinear edges by means of at most 3n - 3 probes, where n is the number of edges of the polygon. This is optimal in the worst-case. This strategy can be extended to probe a family of disjoint polygons. It can also be applied in planar sections of a scene of polyhedra of the class above to find out, in turn, each edge of the scene. If the scene consists of k polyhedra with altogether n faces and m edges, we show that (10,3) n(m + k) - 2m - 3k probes are sufficient to compute the exact shapes of the polyhedra.