Closed brep for analyzing illuminance?

Is it necessary to have a closed brep for analyzing illuminance and UDI?


I have a room and I want to analyze illuminance and UDI

is it impotant the direction of all the surface normals of walls and roof?

(I know it’s essntial for floors)

If you’re not using special materials such as mirror then the direction of surface normal is not important for daylight simulation. At the same time if you don’t assign RADMaterial explicitly Honeybee will use normal direction to identify the surface type and assign the material.

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Thanks alot

Hello Mostapha, I have currently been experiencing a similar issue.
In my gridbased analysis I want to calculate the illuminance.
The weather file is related to Palermo (Italy).
As you can see in the first pics: I have this building with a specific orientation and a curtain wall on the northern and western sides. East side is totally blind. Very low % of fenestration in the southern side.
the grid is placed on the ground floor.
In the model there are rad materials for ceilings (normals face down) and pavements(normals face up), and also interior glass walls (extraclear glass).
I believe that my results don’t make sense : taking into account sunpath, date (10 am of 21st april), and interferences, can ceiling’s normals affect my results acting “as a sun” inside the building? But also i have high value of illuminance in the southern locals with no fenestration!

this is what i get after removing the ceilings

I don’t understand why i get this high values of illuminance from the north facade, with lower values from west. Now the southern part seems to have more reasonable values.

unfortunately I am not allowed to upload the gh file (discourse says “new user”).

Thank you in advance.

There’s a lot of distance between the building of interest and the context building on the north side. The distance on the west is relatively short. Therefore, it seems that the North is receiving more diffused light than the west. We can look at the file to know more after you obtain the permission to upload it.

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I have carried on , under climate based sky, radiation analysis that show more reasonable results in terms of distribution of the radiation inside the building. The most strange things are very relevant values of lux in the south zone with no fenestration.
Morover by moving the grid to the first elevation illuminance maps have more physical sense.

I believe there is a software problem for ground floor.
May I upload the gh file on google drive to show you the problem?

That would be helpful.

Why I am not still able to upload file except for pictures ?

Internal walls are in white and some in glass. Notwithstanding the grid placed at the ground floor gives me strange results in places with low percentage of fenestration.
Thank you in advance