  We systematically compare filtering methods used to extract topological
structures on SU(3) lattice configurations. We show that there is a strong
correlation of the topological charge densities obtained by APE and Stout
smearing. To get rid of artifacts of these methods, we analyze structures that
are also seen by Laplace filtering. This combined analysis shows that the
topological charge density is more fragmented in the presence of dynamical
quarks.
