This paper presents a solution to interactive navigation planning and real-time simulation of a very large number of entities moving in a virtual environment. From the environment geometry analysis, we deduce a structure called navigation graph, which is the base to our method. After the description of this structure, we introduce a set of algorithms dedicated to answer navigation queries with a set of various solution paths and to execute the planned navigation in an efficient manner. We equally demonstrate method performance and robustness over several examples.