  Weyl semimetals are topological materials with protected Weyl nodes in the
band structure. In these materials the surface states form open curves at the
Fermi surface, Fermi arcs in Weyl semimetals and drumhead states of nodal-line
semimetals. In this work we solve analitically the wave function of the surface
states in a generic continuous model describing Weyl and nodal-line type I-II
semimetals within a slab geometry. Depending on the values of the parameters,
different types of Fermi arcs and drumhead states appear. When the mass terms
are dominant with respect to the Fermi velocity in the Hamiltonian the decay of
the surface states become oscillatory. This property has important consequences
in the stability of surface states in a slab geometry This exact solution can
be used for a better understanding of the behaviour of Fermi Arcs in real
materials and their influence in transport and optical properties. We use these
solutions to study the Joint Density of States at the surface which can be used
to interpret quasi-particle interference data in scanning tunnneling microscope
experiments. We show that oscillatory decay can be distinguish from simple
exponential decay of the surface states in these experiments.
