Information about venetian blind shading WINDOW 7.7

[Matteo Formolli]

Hi everyone,

I wanted to ask you a question about how the spacing of blades of venetian blinds works. My intended result is the one you can see in the picture, consisting of a venetian blind system placed in front of a window 2m high, with a spacing of 200mm between blinds. What I want is to have the first blade in line with the top of the glass, while the bottom one at a distance of 200mm from the glass bottom (the window as no frame, the purpose is to create a BSDF for a daylight study in honeybee+). I sat the shading layer with these information as you can see in (1) and add it to my glazing system (2). To get what I am trying to have is it right put 200mm as Dbot value (highlighted in red in the picture) or should I leave it 0? Is not clear to me how the program manages the two spaces at top and bottom, would it be great if you can confirm that what I am doing is right or otherwise suggest me how to do it.

The server is stopping me from adding pictures as attachments, so you can find them at this link:

https://drive.google.com/drive/folders/19BuGm94G9sMybc6UJxiYrUxWxiS-8o60?usp=sharing

Thank you in advance for your support,

Best,

 

Matteo

[Jacob C. Jonsson (LBNL)]

Hi Matteo,

WINDOW is using a radiocity model to predict the distribution of light through the Venetian blind system based on the slat properties and geometry for one period of the slats and then pretending that the layer is homogeneous.  

That distribution is then used for the whole layer area, so effectively you get a homogeneous layer where every point has the same properties.

By adding Dbot and Dtop you are creating air at those edges reducing the area of the homogeneous layer.

Good luck,

Jacob