The common envelope binary interaction is a right of passage for the formation of compact evolved binaries, such as those that eventually give rise to supernovae Type Ia and detectable gravitational wave radiation. Yet simulations are still failing to provide a prescription for how this interaction takes places and how it depends on the parameters of the participating stars. Population synthesis models predict and interpret population sizes of various star classes and rates of phenomena. At present they have to invent ad hoc prescriptions for the common envelope interaction resulting in uncertainties that sometimes are order of magnitude large. In this presentation I will discuss some highlights of our latest 3D simulations and how these are being constrained by observations of transients, jets and planetary nebulae.