[Radiance-general] 5Phase & proxy geometry

[Andrew McNeil]

Hi Chantal,
You should be able to use a non-klems and non-tensor tree BSDF as long as
the angle basis can be described using the format described in the XML
schema (not all can - I've maintain hacked version of Radiance to use a
BSDF angle basis that I've developed). If you send me the XML file I can
look to see what could be causing the problem.

Yes, there are tools for resampling BSDF files.
bsdf2klems :
http://www.radiance-online.org/learning/documentation/manual-pages/pdfs/bsdf2klems.pdf
bsdf2ttree :
http://www.radiance-online.org/learning/documentation/manual-pages/pdfs/bsdf2ttree.pdf

Andy




On Sun, Nov 3, 2013 at 8:53 AM, minchaca <miinchaca at gmail.com> wrote:

> Hi Andy
>
>
>
> Thanks a lot for your help with all my questions. I found the solution to
> the last one... (Not really worth mentioning!!)
>
>  :))
>
>
>
> Regarding my previous 1st. Question:
>
>
>
> I tried to create a *glazing_bsdf.rad* file using one of the cfs.xml
> files that we have in the lab. I’ve got the message:
>
> “Unsupported IncidentDataStructure for BSDF”, I assume this means that
> this is not a ‘tensor tree high resolution BSDF”.
>
> This might be a silly question but: if there is a way to resample the
> tensor tree BSDF into a Klems basis BSDF, is there any way
>
> to do the other way around? Or...perhaps this 'error message' means
> something else..?
>
>
>
> I thank you in advance for your help again!!
>
>
>
> Chantal.
>
>
> 2013/11/1 Andrew McNeil <amcneil at lbl.gov>
>
>>  Hi Chantal,
>>
>> 1.- I’m not sure of the use of the ‘BSDFproxy polygon inside’ included in
>>> the glazing_bsdf.rad file.
>>>
>> The BSDF material is applied to this surface. It allows Radiance to use
>> the BSDF data in lieu of sampling the geometry during the direct sun
>> simulation.
>>
>>
>>> If the latter was generated by genBSDF and includes already the
>>> dimensions of the venetian blind, the model, the glazing, and the thickness
>>> is also specified…why do we need to specify the coordinates of the polygon
>>> (same of the glow material) in this file?
>>>
>> The BSDF is not always produced by genBSDF, it can come from WINDOW or
>> from measurement as well. But regardless, the intention is that optical
>> data in a BSDF file is not specific to a size of window, and so you could
>> use it in various sized windows.  For example if lightlouver produces a
>> BSDF for their product using genBSDF for one project you might want to use
>> it in a 2m window for one project but a 3m window for another. Addtionally
>> there may be times when you want to use a different thinckness for the
>> simulation.  I can think of probably half a dozen reasons why you might not
>> want to use dimensions baked into a BSDF file, an as is typical with
>> Radiance we lean towards generalization.
>>
>>
>>>
>>>
>>> I also wonder if we need to use proxy when only if we have a system such
>>> as venetian blinds. Is possible to use it also if we have a daylight system
>>> as thick as a glass pane such as lasercut panel 6mm?
>>>
>> Yes, but it isn't worth it unless you have a good Radiance material model
>> for the lasercut panel.  Otherwise you're better off using the BSDF
>> (assuming it was measured).
>>
>>
>>>
>>>
>>> I guess that I can shorten this question by: what would be exactly the
>>> function of the proxy geometry?
>>>
>> The BSDF, even high resolution tensortree BSDFs, are spatially averaged.
>>  A venetian blind that is angled to admit stripes of light modeled with
>> only a BSDF will result in a rectangular patch of intermediate brightness.
>>  Using proxy geometry results in bright sun alternating with dark shadows.
>>
>>>
>>>
>>> 2.- Regarding this, in the tutorial you have to rotate the geometry in
>>> order to generate the two xml files (section 6.2) my
>>> silly-silly-super-silly question is:  what would be the orientation of
>>> the resulting xml file? Are we re-orientating it by the last three values
>>> of the orientation vector in the glazing_bsdf.rad ?
>>>
>> The WINDOW XML file standard says inside is +Z outside is -Z, up is +Y.
>> In Radiance we use up as +Z and inside and outside, well it depends on the
>> space your modeling.
>>
>>
>>>
>>>
>>> 3.- I have a final question that just came now when trying the 5Phase:
>>> What would be the number to use in rcontrib –bn when creating the
>>> direct-sun-coefficient-matrix?
>>>
>>> As I understand, it represents the number of sky patches, and it will
>>> generate the values of the RGB in the output file. But, if I use –e MF:6 –f
>>> reinhart.cal –b 5186, I obtain a matrix result with 31116 columns, which is
>>> the number of sky patches six times? Please tell me where am I wrong.
>>>
>>
>> There should be three values per skypatch (R G and B) I don't know why
>> you are getting twice as many.  Can you send the full command you are using?
>>
>> Andy
>>
>>
>>
>>
>>
>>
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>>
>
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