  Aims: We examine the movements of mass elements within dense fibrils using
passive tracer particles (corks) in order to understand fibril creation and
destruction processes.
  Methods: Simulated fibrils were selected at times when they were visible in
an H$\alpha$ image proxy. The corks were selected within fibril H$\alpha$
formation regions. From this set, a cork was selected, and the field line
passing through it was constructed. Other fibrilar corks close to this
fieldline were also selected. Pathlines were constructed, revealing the
locations of the mass elements forward and backward in time. The forces acting
on these mass elements were analysed.
  Results: The main process of fibrilar loading in the simulation is different
to the mass loading scenario in which waves steepen into shocks and push
material upwards along the fieldlines from near their footpoints. Twisted low
lying fieldlines were destabilised and then they untwisted, lifting the
material trapped above their apexes via the Lorentz force. Subsequently, the
majority of the mass drained down the fieldlines towards one or both footpoints
under gravity. Material with large horizontal velocities could also elevated in
rising fieldlines, creating somewhat parabolic motions, but material was not
generally moving upward along a stationary magnetic fieldline during loading.
  Conclusions: The processes observed in the simulation are plausible
additional scenarios. Criteria for observing such events are described. It is
desirable that our simulations can also form more densely-packed fibrils from
material fed from the base of field footpoints. Experimental parameters
required to achieve this are discussed.
