Abstract: Some observed supernova remnants (SNR) are highly asymmetric. Multiple physical processes have been put forth to explain this phenomena, but the detailed physics of supernova explosions is still unknown. I am presenting the three dimensional SPH simulations of SNR development under the effects of velocity and density perturbations within the oxygen shell of progenitor stars (modeled after the progenitors of Cassiopeia A and G292 remnants). We hope to show that realistic introduced perturbations will produce asymmetry in the resulting remnant. Multiple perturbation modes were explored in this work, with unperturbed models for comparison. The simulations are linked to the observed asymmetries to gain greater understanding of the supernova explosion engine.