Dear Ladybug/Honeybee Community,

I am studying for a paper in which I will explain my work mathematically. I used radiationAnalysis component in the work. Therefore, I am looking for the calculation function behind this component. It would be great if you point out any reference?

Thank you for your help,

Mustafa

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.

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

Navid,

Here is what happens inside the component.

radiationAnalysis.gh (490 KB)