Having a play at localising regions on a mesh. Still needs a lot of work but you may find it useful Babylon.js Playground
graph.color(856, 4, BABYLON.Color3.Red()); // facet number, depth, color
depth 0, just facet, 1 facet plus ones that share a vertex with the given facet, 2 facet, plus adjacent facets and the facets adjacent to the adjacent facets