In this paper, a quadrotor path-planning problem while avoiding obstacles, in different shapes and sizes, is considered. The quadrotor is assumed to pass by a set of scattered points or regions defined according to the desired mission following the shortest path. The problem is solved by using a two-scale proposed algorithm. In the first scale, multi-directional optimal Rapidly-exploring Random Trees (RRT) based algorithm is used to define the shortest paths from each point to its neighbors. By means of the inter-costs provides by the first-scale algorithm, in the second scale, the overall shortest path is obtained by solving the Traveling Salesman Problem (TSP) using Genetic Algorithms (GA). The effectiveness of the proposed algorithm is verified with numerical simulations.