  The formation of planets with gaseous envelopes takes place in protoplanetary
accretion discs on time-scales of several millions of years. Small dust
particles stick to each other to form pebbles, pebbles concentrate in the
turbulent flow to form planetesimals and planetary embryos and grow to planets,
which undergo substantial radial migration. All these processes are influenced
by the underlying structure of the protoplanetary disc, specifically the
profiles of temperature, gas scale height and density. The commonly used disc
structure of the Minimum Mass Solar Nebular (MMSN) is a simple power law in all
these quantities. However, protoplanetary disc models with both viscous and
stellar heating show several bumps and dips in temperature, scale height and
density caused by transitions in opacity, which are missing in the MMSN model.
These play an important role in the formation of planets, as they can act as
sweet spots for the formation of planetesimals via the streaming instability
and affect the direction and magnitude of type-I-migration. We present 2D
simulations of accretion discs that feature radiative cooling, viscous and
stellar heating, and are linked to the observed evolutionary stages of
protoplanetary discs and their host stars. These models allow us to identify
preferred planetesimal and planet formation regions in the protoplanetary disc
as a function of the disc's metallicity, accretion rate and lifetime. We derive
simple fitting formulae that feature all structural characteristics of
protoplanetary discs during the evolution of several Myr. These fits are
straightforward to apply for modelling any growth stage of planets where
detailed knowledge of the underlying disc structure is required.
