  A numerical method to obtain the spectrum of smooth normal-superconductor
junctions in nanowires, able to host Majorana zero modes, is presented.
Softness in the potential and superconductor interfaces yields opposite effects
on the protection of Majorana modes. While a soft potential is a hindrance for
protection, a soft superconductor gap transition greatly favors it. Our method
also points out the possibility of extended Majorana states when propagating
modes are active far from the junction, although this requires equal incident
fluxes in all open channels.
