Recent high-resolution observations of protoplanetary disks have revealed a myriad of fascinating structures such as gaps, shadows, vortices and spirals. In this work, we consider the gravitational perturbation due to a stellar companion on the disc structure through 3D hydrodynamical (gas+dust) simulations. The perturber body can either be on a bound orbit in the case of a binary, or in an unbound (parabolic) orbit for a stellar flyby. We focus on the spirals and the disc misalignment induced by the companion. In particular, we study the dust evolution in these systems and search for characteristic observational signatures. We also discuss the long-term evolution of these discs and its implications for planet formation. As a matter of fact, the resulting planetary architecture (system size, type of planets, belts, etc.) is likely to be affected by the kind of gravitational perturbation experienced by the disc. Thus, based on planet formation theories, we speculate on the possible planetary outcomes.