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pixel counting for adaptive shading

asked 2022-04-25 09:12:53 -0500

Rakhmat Aditra's avatar

updated 2022-04-25 13:59:33 -0500

Hello All,

I am currently researching about adaptive shading. My shading is quite complex geometry, so I model my shading as external shade and I use a grasshopper script, which is working, to create transmittance schedule to model the movement of the shading.

Previously I am using Polygon Clipping for the shadow calculation. The result and err file showed that there is too much polygon overlapped. After many times increasing the limit of polygon overlap, I tried to use the Pixel counting instead.

To test this method, I tried a simpler shading which enclosed all the window. image description

I simulated 3 case with different transmittance schedule: 1. Transparent --> Transmittance value of 1 throughout the year 2. Opaque --> Transmittance value of 0 throughout the year 3. Adaptive --> Transmittance value of 0 or 1 based on certain parameter.

I analyzed the window solar gain. It showed that there is no solar gain at all throughout the year. image description

I already use DetailedSkyDiffuse model and Timestep shading calculation. I am using E+ 9.3, but I already tried to run it in version 9.6 but the result was still the same. And if I run using Polygonclipping, the result did not show the same totally opaque problem. Is it an error in Energyplus or is there anything that I miss? Or it is already solved in the newest version.?

Thank you

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answered 2022-05-02 09:57:04 -0500

This seems to be the same issue as reported here and indeed appears to be a limitation in the PixelCounting shading algorithm.

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Asked: 2022-04-25 09:12:53 -0500

Seen: 78 times

Last updated: May 08