Relative velocities between compact (left) or very porous (right) particles with masses m_i and m_j at the midplane of an MMSN-disk at 5 AU with α = 10^-3. The masses range from single monomers to aggregates containing 10³² monomers. The contours give relative velocities in m s^-1, and the colors indicate the dominating source for the relative velocity: Brownian motion (BrM), turbulence (Trb), settling (Set), radial drift (Rad), or azimuthal drift (Azi). Epstein, Stokes, and Newton drag regimes have been taken into account.