Daylight Factor - light leackage tests give different results

Hi everyone!
I’ve been running some light leackage tests with daylight factor HB component. I made three tests with same model and same radiance parameters (quality of 1 and -ab 6) but different number of analyzis planes (rooms). And for each case I got significantly different leackage results.

Any idea why this might be happening?

Hi @magdalena.stefanowicz, welcome to the forum!

That’s expected. rtrace which is the command that is used by Daylight factor recipe under the hood is sensitive to the size of the scene. Take a look at ambient resolution component in the legacy plugin that helps you with calculating -ar based on the size of the scene, the smallest detail that you want Radiance to capture and the expected ambient accuracy (-aa). Not that the lower the -aa value the higher the accuracy.

If you want to visually see the difference and understand how Radiance works under the hood try the same exercise with rpict. Try to add more geometry to change the bounding box and you will see that the quality of the image will come down because the overall size of the scene has changed and the value for -ar has stayed the same.

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Thank you for the quick and clear reply, @mostapha !