Mathematical function of Ladybug Radiation Analysis

Replies to This Discussion

Permalink Reply by Mostapha Sadeghipour Roudsari on October 24, 2015 at 8:00pm

Hi Mustafa, There are two parts to the calculation.

The first step is generating the sky. Ladybug is using Radiance's gendaymtx to generate the sky. If you set sky density to 0, which is the default value, it will generate a Tregenza sky, and density 1 will generate a Reinhart sky.

The second step is ray-tracing which Ladybug does it in a simplified fashion. It does shoot a ray from every test point to center of every sky patch, and if the point can see the sky patch it calculates the value based on the angle of incident. The simplification is that the calculation doesn't consider reflections between the surfaces and material surfaces. If you need them to be calculated then you need to use Honeybee.

Permalink Reply by Abraham Yezioro on October 24, 2015 at 10:17pm

And you can see this visually in this example:

http://hydrashare.github.io/hydra/viewer?owner=ayezioro&fork=hy...

-A.

Permalink Reply by navid on February 11, 2016 at 4:40am

Hi Mostapha,

Would you please make this more clear and explain more?

"and if the point can see the sky patch it calculates the value based on the angle of incident."

@Abraham, it would be nice to add the above calculation on your example! and compare a horizontal 1x1m surface radiation from 1.Sun-radiation 2.Sky-patch divisions 3.Total radiation from epw

Permalink Reply by Mostapha Sadeghipour Roudsari on February 17, 2016 at 8:29am

Navid,

Here is what happens inside the component.

Attachments:

• radiationAnalysis.gh, 490 KB