  For the simulation of pedestrians a method is introduced to find routing
alternatives from any origin position to a given destination area in a given
geometry composed of walking areas and obstacles. The method includes a
parameter which sets a threshold for the approximate minimum size of obstacles
to generate routing alternatives. The resulting data structure for navigation
is constructed such that it does not introduce artifacts to the movement of
simulated pedestrians and that locally pedestrians prefer to walk on the
shortest path. The generated set of routes can be used with iterating static or
dynamic assignment methods.
