As for an effective A* algorithm, bidirectional A* turns out to be both rugged and efficient.<p>Basically, grab some graph paper. Put your left index finger on start. Right index finger on end.<p>Move your fingers towards each other, avoiding obstacles as you go.<p>Wherever they happen to meet, the path formed by the trail of both your fingers combined is the path to use.<p>That&#x27;s the general idea. It&#x27;s important to trace from both simultaneously, otherwise you run into some degeneracies.