Different Daylight (DF) results on vertical vs horizontal analysis surface

Dear community,

we ran a daylight factor study today and long story short:
Within the same analysis we get different results from a horizontal and a vertical analysis surface.
To my understanding, they should be the same since the analysis surface is broken down into points which are then analysed from all directions, and out points are pretty close to each other.

Does anyone know what’s going on?

That is expected! unless you are using the exact same sensor with the same normal direction the results should be different. I suspect the sensor direction for the vertical section is set to 0, -1, 0 or something like that instead of 0, 0, 1 which is the sensor direction for the horizontal grid.

To clarify, the mesh face centroids are the sensors which pick up light based on the face normals? Does that mean that as soon as the analysis surface is tilted the results will be altered (stairs, escalators, etc)? This makes me wonder, what is the angle of the sensors and how come there is a limitation to sensoring light? Thanks for your time!

If you generate the sensors from a mesh then the mesh normal will be the direction for the sensor. You can always overwrite the normal direction when creating the recipe. Or leave the ptsVectors input empty which means a value of 0, 0, 1 will be assigned to all the sensors by default.


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