Do you need to use Manhattan distance for A* path finding algorithms?

Question

I am working on an A* path finding algorithm with a video from sebastian lague (yt). But I don’t know if I have to use Manhattan distance or if I can use normal pythagoras theorem to measure distance. Do anyone know this?

I am working in c#,unity if that is relevant

Answer 1

Assuming you are allowed to make diagonal moves, then use Pythagorean Theorem to measure diagonal distance, so you'll have a cost of 1 to move horizontally/vertically and a cost of 1.4 to move diagonally. If you use Manhattan Distance to measure diagonal moves, you'll never move diagonally because the cost of each diagonal move would be the sum of the horizontal and vertical movement.

If you're not allowed to make diagonal moves and you're coding your own A* algorithm (as I assume you're doing in that tutorial), then I think it would be better to not consider diagonal moves as valid rather than to assign them an artificially higher weight (like using Manhattan Distance).