AW: light leakage problem

Dear Thomas and Harshada,
we currently have also figured out a light leakage problem that occurs only when working with quite huge models. We did some analysis on that problem and found out the following:

If we measure the daylight factors in a simple box generated with genbox without any openings than rtrace gives us zero values for all measurement points as expected.

If we than add an additional surface that is much bigger than the simple box and do the simulation again (without changing anything else), we receive light in the the completely closed box. We think, we are using appropriate values for -aa and -ar. The result of: biggest_model_length * aa / ar is much smaller than the distance between the measurement points.

Maybe the solution for this problem is using mkillum instead of common windows. We keep on testing...

Regard, Kai.


-----Ursprüngliche Nachricht-----
  Von: [] Im Auftrag von EncaseIndia
  Gesendet: Donnerstag, 24. Juli 2008 15:25
  An: Radiance general discussion
  Betreff: Re: [Radiance-general] light leakage problem
  Hi Thomas,
  Thanks for the feedback.
  I was actually checking my model in radiance without any windows,wherein it showed me light leakage.Its just one corner of the building at which i can see some light ,which is around 250 lux, quite huge amount.
  I deleted all my windows in ecotect and then exported the model in radiance, after so much analysis i could just find the corner from where the light is leaking.
  I have attached the pictures here.
  and I hope you find my english proper. :slight_smile:

    ----- Original Message -----
    From: Thomas Bleicher <>
    To: Radiance general discussion <>
    Sent: Tuesday, July 22, 2008 11:42 PM
    Subject: Re: [Radiance-general] light leakage problem

    On 22 Jul 2008, at 05:57, EncaseIndia wrote:

      hii everyone,
      It seems i have light leakage problem in my model, can ne1 tel m …hw can I fix it…?

    The first thing to do is to identify the source of the problem. Why do you
    suspect 'light leakage'? To high values for daylight factor?

    First check your material definitions. If you have windows and your glass
    material is incorrect too much light might enter the room through the
    window panes.

    If you think that the geometry is the problem try a few fisheye views of the
    inside. Bright pools at the edges of walls/ceilings/etc. indicate a problem.
    If the inside doesn't show anything, place a light source inside and render
    views from the outside without sky.

      Is thr ne odr option except reconstructing model..? I have done my Model in ecotect....

    There is no point in recreating a model if you don't know what was wrong
    with the first one.

    Please also post your questions in proper English and provide as much
    information as you can. If you want us to take the time for meaningful
    replies you should take the time to type an understandable question.



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