[Radiance-general] gensky

[Rob Guglielmetti]

Hi Jia,

On Mar 25, 2010, at 7:20 PM, Jia Hu wrote:
> I have some questions relating to gensky command.
>  
> (1) The book of "Rendering with radiance" says luminous efficacy is set to 179 for all CIE sky models. Is that true for current version?

The 179 lm/watt is the standard luminous efficacy conversion for Radiance, and yes it's still the same for the current version. 

> (2) If I know Solar direct radiation and diffuse radiation, I hope to use Perez's (source: Modeling daylight availability and irradiance components from direct and global irradiance, 1990 solar energy) models (that is, interpolate two CIE sky model according to radiation), is that possible to generate a new sky luminance distribution model by interpolation of two standard CIE model in Radiance in order to calculate the interior illuminance more accurately?

If you know direct and diffuse radiation, you can use gendaylit (recently added to the default Radiance distro) to generate a Perez sky model directly. Check the manpage for gendaylit. I have been using it lately for some studies based on TMY weather file info and it works well!

- Rob