I am trying to run some calculations with BSDF files from Solatube using both DIVA for point-in-time simulations and Honeybee[+] for annual simulations. I was running some test renderings to ensure I had the BSDF files properly oriented and am noticing some major differences between the DIVA renderings and HB+ renderings. Wondering if anyone might know why there would be such a difference in the light distribution - and therefore light levels - considering both images are generated using rpict, contain identical geometry/material definitions, and have very similar radiance parameters.
Below are the images, and I have attached my grasshopper definition (model units in meters) and ZIP file of the DIVA directory. Also below are links to the solatube BSDF files if that is helpful and to some correspondence on the Honeybee discussion board regarding this issue. Any help would be appreciated.
I suspect Sarith's reply on the ladybug forum is on the right track. The DIVA rendering on the left uses an overture pass and also oversamples the image (by default using 2x the specified pixel dimensions, though you can set this). If this is different in HB+, it may explain the difference in the smoothness of the irradiance cache.