      
                % Inner loop over all walls
                for j = 1:length(p1.verlet_w)
                    w = p1.verlet_w(j);
                    
                    % Check for existing interaction
                    if (any(p1.neigh_wid == w.id))
                        % Get interaction object
                        int = findobj(p1.interacts,'elem2',w);
                        
                        % Compute separation between elements
                        int.kinemat = int.kinemat.s