Although visibility graph overcomes the exponential increase in the number of cells in regulargrid when representing a complex game world like 3-dimension (3D) world, the mostcompelling disadvantage of such a representation is that generating a visibility graph has O(n2) complexity (n is the number of nodes). It is not the best solution for pathfinding especially in an outdoor area as shown in Figure 7. Visibility graph with A* algorithm is guaranteed to find the shortest path if one exists on the graph [9].