a. generating data describing particles that represent each of the first and second objects from geometric data for the first and second objects, wherein the data for each particle describes a mass, density, velocity, pressure, stress and energy at a position of the corresponding object, to produce a first collection of particles representing the first object and a second collection of particles representing the second object;

b. grouping particles into sectors to define a computational mesh comprising a plurality of sectors, wherein each sector is a volume region at a position in space;

c. for each of a plurality of select particles, determining neighboring particles that are within a region of influence with respect to each select particle;

d. performing computations pertaining to the interaction of particles in said computational mesh based on the neighboring particles determined for each of the plurality of select particles to produce for a time step updated data for mass, velocity, energy and position for the particles; and

e. repeating (b) through (d) for each of a plurality of time steps;

wherein (c) determining at a current time step comprises searching through particles that are within a bounding volume region comprised of sectors that are within the region of influence at a previous time step and within those sectors in contact with or bordering the region of influence from the previous time step.