It would be nice to be able to have more I/O formats available for simulations, in particular an option to output the phase space of the individual photons, and to launch a simulation from the same. Among other things, that would in turn allow users to bin the final photon states as they please, and implement things like energy-resolved detection...

Thank you for the suggestion. This is planned for GGEMS 2.

We want to support phase-space output for individual photons, and also allow simulations to be launched again from saved phase-space data. This would make user-defined binning, energy-resolved detection, and custom post-processing much easier.

The implementation details are not fixed yet, but this use case is clearly part of the GGEMS 2 roadmap.