I am wondering how I can calculate the view factor for some easy applications. In this case, I am trying to calculate view factors between surfaces on earth and the sky.
In the literature I found that the view factor between a surface inclined at slope b and the sky is as follows: F1 = (1 + cos(b)) / 2
And between the same surface and the ground: F2 = (1 - cos(b)) / 2
My questions: (1) How are these view factors calculated? (2) How can I calculate more complex view factors? E.g. if there is some object between the inclined surface and the sky producing some shadow on it (so part of the sky is not visible).
Thanks a lot for your help & comments! Jens