[Radiance-general] Re: Annual daylight simulations

[Andrew McNeil]

Hi Marija,

I was out all last week for thanksgiving.  I hope my reply is not too late
to be helpful.

I haven't done the three phase method yet. I'm validating my bsdf data and
have been side tracked by other projects.  But I'll get to it soon...

> Question is how to calculate Transmission matrix with BTDF values for the
> specific window or group of windows?
This can be measured via a goniophotometer, exported from LBNL Window, or
simulated using Trace Pro, or radiance using rtcontrib.

> I see it should be some file in xml format, but not sure how to create it when
> classic transmittance and reflectance data are known for the glazing; and also
> what format if has.

The BSDF data should be in LBNL¹s window xml format.  I enquired LBNL about
the format in September and at that time the documentation wasn¹t complete.
I can send you the draft specification I received in September if you like
but it's probably worth contacting LBNL to see if documentation has
progressed.

> Also for non-complex glazing systems (like double or triple glazings, without
> internal blinds and similar), is it possible to compose this BTDF matrix
> "manually"?

LBNL Window 6 will write an xml format bsdf file for data a window system
described in it's program.  I found it helpful to do this to reverse
engineer the XML file format.

But... The three phase method is intended for a system that requires a bsdf
to characterize light transport.  If your material can be characterized
using a standard radiance material (like a simple double/triple glazing
without blinds) than the more conventional daylight coefficient approach
(one-phase?) will be easier, faster and more accurate.

Andrew 



On 11/24/09 12:51 AM, "Marija Velickovic" <maricanis at gmail.com> wrote:

> Hi again,
> 
> I've just found out that, I somehow skipped reading of mails with "BSDF" in
> the subject, and found out that Andrew McNeil had similar problem last month
> 
> In mail 
> http://www.radiance-online.org/pipermail/radiance-general/2009-October/006296.
> html there is a note about script for BSDF calculation based on rtcontrib.
> 
> Andrew, were script calculation results good?
> Did you manage to make complete 3-phase calculation?
> 
> Marija.
> 
> 
> 
> 
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