  Planetary nebulae (PNe) and their central stars (CSs) are ideal tools to test
evolutionary theory: photospheric properties of their exciting stars give
stringent constraints for theoretical predictions of stellar evolution. The
nebular abundances display the star's photosphere at the time of the nebula's
ejection which allows to look back into the history of stellar evolution - but,
more importantly, they even provide a possibility to investigate on the
chemical evolution of our Galaxy because most of the nuclear processed material
goes back into the interstellar medium via PNe.
  The recent developments in observation techniques and a new three-dimensional
photoionization code MOCASSIN enable us to analyze PNe properties precisely by
the construction of consistent models of PNe and CSs. In addition to PNe
imaging and spectroscopy, detailed information about the velocity field within
the PNe is a pre-requisite to employ de-projection techniques in modeling the
physical structureof the PNe.
