The paper introduces foundations of the "Flexible Routing Method" that belongs to the topologically-geometric type. It develops the idea to divide the routing problem on two separate successive stages: topological and geometrical. At the first stage it was suggested to use a discrete topological model as Delaunay triangulation or/and Voronoi polygons to describe topology. The explicit and implicit topology models are offered which describe the relative topological nets location without specifying their geometrical characteristics. At the second stage possible is the laying the nets of arbitrary configuration: orthogonal, piecewise linear, curvilinear, under arbitrary angles and arbitrary widths.