Recent years have brought a tremendous progress in the modelling of self-consistent neutrino driven supernova (SN) explosions. Not only that the first 3D simulations have become accessible and have shown successful explosions, also first long-term simulations up to the SN breakout from the progenitor have been performed with realistic initial conditions. These studies allowed to investigate the development of hydrodynamical instabilities during the expansion of the ejecta. Also the observations with 3D information about the structures of different elements and molecules in young and nearby supernova remnants (SNR) have reached a state at which they can be compared to 3D long-time simulations. However, to challenge these models with observations is not easy. It can be straight forward, e.g. when comparing abundances of radioactive elements to the simulations, but can be a major problem when we want to study e.g. emission lines of molecules which in the first place have to be formed and second have to be excited. In ordinary SNR the ejecta structures are determined by the explosion engine, the instabilities during the propagation through the progenitor, the interaction with various shocks and the ISM. We present recent long-time, 3D simulations of core-collapse supernovae and describe what can be learnt from comparing simulations to observations.