[Radiance-general] Could RTRACE produce two outputs (picture and values)?

[Greg Ward]

Hi Mirjam,

I want to agree with and embellish Christopher's reply.  Adding an ambient file will make the second simulation take very little time if indeed it is evaluating the same set of points.  However, you cannot directly compute illuminance from luminance or vice versa except under very special circumstances (i.e., reflection from a uniform diffuse surface).  They are fundamentally different calculations.

You may also try the -n option to rtrace, which combined with the -af option will speed the calculation considerably on modern multicore machines.

Cheers,
-Greg

> From: Christopher Rush <Christopher.Rush at arup.com>
> Date: March 28, 2013 9:41:39 AM PDT
> 
> If you add a parameter to both rtrace commands such as “-af simulation1.amb” it will save an ambient cache in your current working directory and make the second command run faster. You will want to be sure that your ambient calculation parameters are the same for both, in your case it looks like you’re taking the rtrace defaults for both. If you revise your model or calculation parameters, you will also want to manually delete the ambient cache before you run again, because you will either see strange results or an error message if you inadvertently try to use the old cache for a new calculation.


------------
> From: "Laarhoven, M. van" <m.v.laarhoven at student.tue.nl>
> Date: March 28, 2013 7:24:34 AM PDT
> 
> Dear all,
>  
> Just a short question, unfortunately I wasn’t able to find the answer on the Radiance-community:
>  
> Is it possible to create two outputs using RTRACE:
> -          a .hdr picture and
> -          a text file containing illuminance values.
>  
> In case of a virtual plane, rtrace has to be used instead of rpict (as explained in the Radiance Tutorial). Now, I’m doing the same simulation twice in order to get 2 outputs which takes a lot of time. Isn’t it possible to create 2 outputs through only 1 simulation?
> If not, could pvalue help me on this one? And if yes, how? Or would pvalue only would give me luminance values?
>  
>  
> First simulation:
> echo "     Rtrace illuminance "
> vwrays -x $Dims -y $Dims -vf viewfile.vf \
> | rcalc -e '$1=$1; $2=$2; $3=0.75; $4=$4; $5=$5; $6=1' \
> | rtrace -w -ab 3 -fac -I -ov `vwrays -d -vf viewfile.vf -x $Dims -y $Dims` scene.oct >  Outcome.hdr
>  
> Second simulation:
> echo "     Rtrace illuminance values "
> vwrays -x $Dimstable -y $Dimstable -vf viewfile.vf \
> | rcalc -e '$1=$1; $2=$2; $3=$3; $4=$4; $5=$5; $6=1' \
> | rtrace -w -I -h -ov -ab 2 `vwrays -d -vf viewfile.vf -x $Dims -y $Dims` scene.oct | rcalc -e '$1=$1*179' > Outcome.txt
>  
>  
> Thanks in advance for your help!
>  
> Best regards,
> Mirjam
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