Sunlight passing irregular glass thickness

Hi,
I what to setup a model to visualize / run a daylight calculation, with light passing thru a glass material with various irregular thickness, for example old glass where caustic light effects might appear on a interior surface.

Could this be done with a custom BSDF material? Or its I a way to make a 3d object into a glassmaterial…?
Any thoughts on this anyone?

Inspired by this:
https://www.researchgate.net/publication/327594722_Modeling_the_effects_of_daylight_scattering_by_window_glass_The_case_of_6th_century_Hagia_Sophia_in_Istanbul

Lars Grobe, one of the authors of that paper, is pretty active on the Radiance Discourse https://discourse.radiance-online.org/ . You might get a direct reply from him if you post your query there.

With regards to seeing caustics, if you model the glass as a volume using Dielectric and use Photon Mapping, you’d most likely see some effects of caustics. I think that would be the case with BSDFs and Photon Mapping too, however, it is a fair amount of work to realistically model glass panels/volumes with genBSDF.

I had played around with it a few years ago by modeling a swimming pool (with dielectric and noise function to incorporate water). The caustics from the underwater lights can be seen on the walls of the pool in some of the images.

Andy Mcneil had discussed his own experiments with Photon Mapping at the 2015 Radiance workshop.


You can probably get a few pointers from his presentation file.

Regards,
Sarith