  Double deeply virtual Compton scattering (DDVCS) is the process where an
electron scatters off a nucleon and produces a lepton pair. The main advantage
of this process in contrast with deeply virtual and timelike Compton
scatterings (DVCS and TCS) is the possibility of directly measuring GPDs for
$x\neq\pm\xi$ at leading order in $\alpha_s$ (LO). We present a new calculation
of the DDVCS amplitude based on spinor techniques which produce expressions for
amplitudes that are perfectly suited for their implementation in numerical
simulations. Elements of impact studies, including predictions for experiments
at JLab12, JLab20+ and the Electron-Ion Collider (EIC), are studied by means of
the PARTONS software and the EpIC Monte Carlo event generator.
