Hi @gaetano.christian.ruvio, that comparison is only valid for Honeybee[+], which runs rcontrib and rfluxmtx. The sampling option is not present in conventional Radiance tools like rpict and rcontrib because they employ ambient caching algorithms instead of relying on pure Monte Carlo raytracing. For a comparison of rad parameters for conventional Radiance, you can refer the tool created by @MingboPeng : http://www.ladybug.tools/design_explorer_lite/?ID=RNEAu2