I believe this is "flow fields" or "potential fields" -- as mentioned by other commenters, scaling it with graph size and destination-count are two of the main

I believe this is "flow fields" or "potential fields" -- as mentioned by other commenters, scaling it with graph size and destination-count are two of the main issues with it. In SimAirport we use flow fields, they're great for crowds & they scale incredibly well with agent count. We use them for "long distance" traversals, and then we use "local" A-star like grid search for the "last-mile" of an agent's journey. For flow-fields, we start by dividing everything up into "sectors" based on game logic -- and then further, into "sub-sectors", essentially just basic abstractions of the graph with smaller node counts. It does have an impact on path quality but for the scale we operate at in SimAirport the trade-off is a no brainer. The abstractions then limit the flow-field's graph size & the destination-count that any given subsector (abstracted-node) can have -- essentially it's a hierarchical (pseudo HPA-star) approach to flowfield pathfinding / navigation, and the abstraction also has major benefits for reachability queries & game-logic driven "rules" (ie load-balancing of capacity-constrained paths [stairs/escalators], one-way paths [ie directed graph algos], etc).