Overdensity maps noise effects with different codes and smoothing. The top row corresponds to BPM, where the overdensity is calculated directly with the solution of Continuity+Poisson equations. The second row shows the PM overdensity after applying CIC to the particle distribution. The two lowest rows correspond to the Tree code after applying CIC, using a grid resolution of 1.0 (512³ cells) and 0.3 (1720³ cells) kpc, respectively. The highest resolution hardly shows the wake and global response. However, the smoothed case shows a host halo response close to the PM case, demonstrating a dependence on the grid smoothing.