[Radiance-general] Ambient exclude transfomed material in instances

[Jack de Valpine]

Hi Greg and Iebele,

I have a comment and a question on this.

First, Iebele, I have also just gotten a 3D xfrog tree. FYI, it is 
possible to generate an obj, convert to a radiance mesh and use Local 
u,v coordinate mapping to get the leaf and bark materials to apply. I 
have a tree right now that basically has a few materials defined for it:

   1. bark with colorpict modifier
   2. leaf with colorpict modifier
   3. leaf-mix mixpict - this uses an alpha version of the leaf to mix
      between void (ie where the alpha is black) and the leaf material (2)

The question for Greg is this, to exclude the leaves from the ambient 
calculation what needs to be listed in the exclude file the "leaf" 
material and/or the "leaf-mix" material?

Iebele, the one thing to note is that the obj file that comes out of 
xfrog does not play well with obj2mesh or obj2rad. Thus I have to bring 
it into PolyTrans and re-export as an obj to get a file that radiance is 
happy with.

Best,

-Jack

Gregory J. Ward wrote:
> Hello Iebele,
>
> Since you have too many materials in your "ambient exclude" list, 
> you're best hope is to switch to an "ambient include" list, instead.  
> Create a file listing all of the materials, hopefully not xform'ed and 
> duplicated like your leaves, that you would like to include in the 
> interreflection calculation.  These can be put in a file and 
> incorporated with a single -aI option.
>
> The other alternative is to switch off the irradiance cache using -aa 
> 0 and assign other parameters to make the problem tractable over all 
> surfaces.
>
> -Greg
>
>> From: iebele <info at iebele.nl>
>> Date: April 2, 2007 9:08:03 AM PDT
>>
>> Hi,
>>
>> I have a complex scene in which I use instances which I want to 
>> exclude from ambient calculation.
>>
>> The problem is that I use !xform  ..... with file A that include 
>> materials to create another file B  that is later used as an instance.
>> I need the materials in file A excluded from ambient calculation.
>> The exclusion does not seem to work in my case, which makes the 
>> rendering times enormous ( lightyear - 0.01 % progress per hour in 
>> the picturel, very very much rays )
>>
>> Any help is most  welcome.
>>
>> -Iebele
>
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-- 
# Jack de Valpine
# president
#
# visarc incorporated
# http://www.visarc.com
#
# channeling technology for superior design and construction

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