[Radiance-general] Annual simulations + BSDF

[Andrew McNeil]

Hi Greg, 

I¹ve written a script that does this, it¹s been running over the weekend.
I¹ll share the script if the results are consistent with expectations ( I
give it a 40% chance ).

I decided to use both phi/theta input and output directions, because that¹s
consistent with the window 6 BSDF specification that mkillum uses.

I look forward to seeing your presentation slides for the conference next
week.

Andy




On 10/18/09 11:26 AM, "Greg Ward" <gregoryjward at gmail.com> wrote:

> Hi Andrew,
> 
> I guess I should write a program or script to create a BTDF file for an
> arbitrary shading system.  It's not particularly difficult to do this using
> rtcontrib, but I need to find time to do it.  The next couple of weeks are
> crazy between the workshop and the HDR Imaging book deadline, so I don't think
> I'll get to it before then.  I won't be much help with your deadline,
> unfortunately.
> 
> -Greg
> 
>> From: Andrew McNeil <andrew.mcneil at arup.com>
>>  
>> 
>> Date: October 16, 2009 9:34:13 AM PDT
>>  
>> 
>> 
>>  
>>>  Hi Greg,
>>>  
>>>  Thanks for your reply.  Unfortunately I¹m not going to Boston.  Now I have
>>> yet another reason to wish I was going.
>>>  
>>>  I¹m glad you¹ve been able to further develop the 3-phase method.  I see
>>> increasing demand for this type of analysis for complex façade shading
>>> systems.  This is the fourth time I¹ve started down this route ­ the other
>>> three times stopped abruptly for various reasons.  Twice before with
>>> panelite products and once with an engineered scattering window film.  The
>>> email I sent yesterday was a  partially complete left in my drafts folder
>>> from two months ago - the last time this I was looking into this approach.
>>>  
>>>  I don¹t have a hard deadline yet.  The goal for now is to develop a working
>>> model and then focus on accuracy later.  Ideally I¹d have something that
>>> works in the next 2 weeks.
>>>  
>>>  Hopefully Panelite will have measured BTDF data in a few months that we
>>> slot into the analysis.  If measured BTDF data doesn't become available then
>>> we¹ll focus on improving the accuracy of the simulated BTDF.
>>>  
>>>  So I guess my first step is approximating a BTDF with Radiance.  I was
>>> thinking I could a uniform sky above the panelite model as input and a
>>> hemisphere of points below as sensors.  With rtcontrib I could determine the
>>> light output in a direction for each input direction.  The input directions
>>> could be tregenza sky divisions (?).  The output could be phi/lambda
>>> directions (?).  I imagine the key to a decent BTDF is lots of samples for
>>> each output direction.  Maybe I create a grid of 1000(00?) points in a plane
>>> just below the panelite and use a script to create a hemisphere of sensor
>>> points centered at each grid point.
>>>  
>>>  I know very little about BTDF¹s and even less about creating them so I
>>> could use any tips, tricks, guidance, watch its, how are you going to
>>> account for?s and examples that anyone is willing to offer.
>>>  
>>>  Thanks,
>>>  Andy
>> 
>> 
> _______________________________________________
> Radiance-general mailing list
> Radiance-general at radiance-online.org
> http://www.radiance-online.org/mailman/listinfo/radiance-general

____________________________________________________________
Electronic mail messages entering and leaving Arup  business
systems are scanned for acceptability of content and viruses
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://radiance-online.org/pipermail/radiance-general/attachments/20091018/cfa4dc99/attachment.htm