Time based rendering

[EMwavelength]

Hi,
I am sorry if this is a request or an already implemented feature, but i want to know if mitsuba 3 is able to simulate transient effects of light i.e time based rendering both camera and non-camera space . Since mitsuba 3 is research oriented i like to know if such feature is already implemented, if not will it be in roadmap or future cosideration?

[alhirzel]

I'm not a core developer but have worked in this area before. Mitsuba supports tracking a time for rays as they propagate through a scene:

https://github.com/mitsuba-renderer/mitsuba3/blob/master/include/mitsuba/core/ray.h#L33

Existing integrators seem to treat this only wrt the shutter open/close, for example:

https://github.com/mitsuba-renderer/mitsuba3/blob/master/src/integrators/ptracer.cpp#L171

I suspect that ray length does not couple into this quantity for any of the built-in integrators. You would need to write your own, potentially taking into account the medium properties and disabling the built-in treatment of IOR at the interfaces of heterogeneous media (since it would be redundant with your formulation).

I suspect that this may not have the necessary precision for some applications (e.g. time of flight in the realm of nanoseconds will struggle unless you use double precision arithmetic everywhere).

[EMwavelength]

Thank you for the answer.