How to find all possible destinations, within a certain walking distance of a unit? I have a standard 2D grid that i use for pathfinding. I already use A to find the path of my units when I want to move them around. What I need to implement now is a preview of all possible destinations of the unit when it is selected. Here is what I want to achieve. The yellow orange cells represent the possible destinations. I want to make this as optimized as possible, because it can be executed on very big maps and for multiple units. I have something in mind but I wonder if there is better approach for this. Here is my idea Get a list of all cells that are walkable in a square around my unit. The square will be from Unit.X Unit.Speed to Unit.X Unit.Speed for X axis and Unit.Y Unit.Speed to Unit.Y Unit.Speed for Y axis. For each element in this list, execute A search to see if it is possible to find a path. By doing the search for only the cells that are within my unit range I should be able to do this on big maps. Basically this is the same feature that we have in games like Heroes 3 and many other turn based games. Screenshot I was also wondering when it is a good idea to execute this pathfinding logic. When you select a unit (might result a spike) or when something moves on the map to update the list of all possible destinations of all units on the map.