Weird DF Results

Hey Team LB,

I’m currently working on a DF calculation script for multiple rooms, and when I tried to test the result of the calculation, it turned out some very odd results. Rooms without windows shouldn’t have 0 value for the DF, but for some reason some of those rooms have positive DF values. So, I was wondering if there was any mistake in the script, but I couldn’t figure out what the mistake was. If you guys could look into my script and point out what the mistake was, it would be amazing! (521.5 KB)

Thanks in advance!

Hi @zengwoo1028,

For Radiance studies it is better to create the model in meters. You can do this before creating the model, or use HB Scale after creating the model.

The second thing you should look at is the ambient resolution (-ar), which is one of the Radiance parameters. This depends on the size of the scene. You can HB Ambient Resolution to calculate an appropriate value. See more here, or look at the search results on the forum if you want to see more examples.

One of the reason why I advice you to use meters, is that Radiance does not know if the model is in meters or millimeters. If you use millimeters the scene size will be very large in your case, and since the -ar depends on the size, you would need a very large value.

The final thing to look at is your ground surface. You could easily reduce the size (and reduce the required -ar).

Thanks for the explanations, it solves the problem :slightly_smiling_face: