Compute picks a line direction via a 1D interval intersection (half-circles per edge). If possible, it is topology-compatible (all edges forward). The new edge costs are max(0, ψ(v) - ψ(u)). Below you can see all paths Start → Target under the new costs; shortest paths are highlighted in green. Optionally, click a path that will be prioritized for direction selection.The method is described here and presented here