Radiance-general Digest, Vol 135, Issue 18

Hi Zack,

Many thanks for your clarifying.
I have a more general question just now raised (as a beginner in this field). I wish if you can help me to answer:

As Daysim and SPOT Pro's main difference is mainly how to treat with sun and sky components, is that applies to all radiance-based-engine tools (including Radiance command-line approach itself)? By other words, is the way sun-and-sky-being-treated the main motivation to go for radiance-based-engine-tools rather than simple tools (i.e. like Ecotect)? So if someone needs to just investigate how different complex fenestration systems will affect indoor daylight coefficients (no illuminance levels nor pictures needed), there is no need to generate BSDF data for those CFS and even no need to use radiance?

Does that sound right?

Sorry for my long emails, but really this will help me a lot at my early stages.

Best regards
Ikrima

···

-----Original Message-----
From: [email protected] [mailto:[email protected]]
Sent: 13 May 2015 18:46
To: [email protected]
Subject: Radiance-general Digest, Vol 135, Issue 18

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Today's Topics:

   1. Re: Rendering using Radiance_As Beginners - SPOT Pro released
      (Zack Rogers)
   2. Re: rcontrib for rendering - missing required modifier
      argument (Greg Ward)
   3. Question concerning installing Radiance in Mac (zhekong)

----------------------------------------------------------------------

Message: 1
Date: Wed, 13 May 2015 10:04:09 -0600
From: Zack Rogers <[email protected]>
To: Radiance general discussion <[email protected]>
Subject: Re: [Radiance-general] Rendering using Radiance_As Beginners
  - SPOT Pro released
Message-ID:
  <CAAP856wiq_J37fj1YV+tGv_UK9CSRosHcMOjw6JVDt+6gft1zw@mail.gmail.com>
Content-Type: text/plain; charset="utf-8"

Hi Ikrima,

Answers below:

Regarding SPOT Pro, it seems that it can work out annual simulation for CFS

with BSDF but for grid points we still need to use command-line (as
you clarified).

SPOT does automatically calculate a workplane level (height can be
specified) grid of points. In you query it sounded like maybe you were interested in possible other illuminance points (eye level or wall) for which you may need to go behind the scenes and work with classic Radiance.

Also, we still need to use command-line (radiance) to generate BSDF
that will be used with SPOT Pro . Is that right?

BSDF files can come from several places: 1) there is a small library of generic ones in SPOT. 2) You can generate them via genBSDF and command lines. 3) LBL's Window 7.3 program can generate them 4) If small enough samples you can have physical goniophotometer measurements that would need to be converted to the Radiance BSDF format 5) use companies like mine, we offer daylighting performance characterization and BSDF creation for complex optical daylight systems as service.

Also, what is the difference between SPOT Pro and Daysim tools in terms of

accuracy and flexibility (as both using Radiance engine)?

They both use Radiance for all simulation they just have two different approaches to annual simulation. DAYSIM uses Daylight Coefficients, breaking the sky into atleast 145 patches and calculating the contribution from each and then using this data to simulate throughout the year. 1, 2, 3 and 5phase methods all just treat the sun and sky components in different ways. SPOT interpolates from a range of design day calculations to simulate throughout the year. In my opinion both have some advantages and disadvantages in terms of accuracy and speed and how they can treat window treatments. The annual comparison's I have seen show very similar results between the two methods but I do feel more annual daylighting simulation studies and validation is needed of all methods in general.

Regards,

Zack

--
Zack Rogers, P.E., LEED AP BD+C
Daylighting Innovations, LLC
808 S. Public Road, Suite 200
Lafayette, CO 80026
(303)946-2310

www.daylightinginnovations.com
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Message: 2
Date: Wed, 13 May 2015 10:41:02 -0700
From: Greg Ward <[email protected]>
To: Radiance general discussion <[email protected]>
Subject: Re: [Radiance-general] rcontrib for rendering - missing
  required modifier argument
Message-ID: <[email protected]>
Content-Type: text/plain; charset="windows-1252"

Hi Urtza,

You should not be using the file "klems_ang.cal" but something like "klems_full.cal" or klems_int.cal. This is why Nkbins was undefined, and probably at least one reason your simulation is not working.

Best,
-Greg

From: [email protected]
Subject: Re: [Radiance-general] Fwd: rcontrib for rendering - missing required modifier argument
Date: May 13, 2015 8:14:16 AM PDT
Hello Christopher,

Thank you for your response.
I think that in the radiance-4.2.2-win32.exe there is not the ximage program. I usually use RadianceIV.exe program from Ecotect.

C:\Radiance\test\20150505\vmx>ximage window_000.hdr
"ximage" no se reconoce como un comando interno o externo,
programa o archivo por lotes ejecutable.

However, I find klems_full.cal file that it has all information about kbinS and Nkbins.
Now I have 145 .hdr files. They have light source, but the room walls are black (is it usual?)

In reference to pcompos, window1_*.hdr is invalid argument. Do you know why?

C:\Radiance\test\20150505\vmx\images>pcompos -a 10 -b 1 1 1 "window1_*.hdr" > al
lwindow1.hdr
window1_*.hdr: Invalid argument

Thank you in advance,
Kind regards,
Urtza.

Christopher Rush <[email protected]> escribi?:

What do you use to view the HDR image? Try typing:

ximage -e auto window_000.hdr

This will automatically adjust the exposure of your image upon initially opening the file. It could be that your image does have non-zero values but the exposure is skewed in your viewpoint making it look black with the default exposure value.

Or type

ximage window_000.hdr

then hit the ?a? key while ximage is active to view it with automatic exposure

while ximage is active you can also hit the ?=? key and click a point in the image to adjust the exposure according to various points in the image

From: [email protected] [mailto:[email protected]]
Sent: Wednesday, May 13, 2015 5:01 AM
   
However, generated window_000.hdr file does not have light. It is a black image, even though, the render generated by rvu of the room it is ok.
Do you know why does it happen?

Thank you!
Kind regards,
Urtza

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Message: 3
Date: Wed, 13 May 2015 11:10:03 -0500
From: zhekong <[email protected]>
To: [email protected]
Subject: [Radiance-general] Question concerning installing Radiance in
  Mac
Message-ID: <[email protected]>
Content-Type: text/plain; charset="utf-8"

Hi all:
I?m starting to learn Radiance and tried to install it in Mac. I followed the video of installation online and got errors in attachment. I ran a test and got another error in the second attachment.
Could someone let me know how I should fix it?
Thank you in advance.
Zhe

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Hi Ikrima,

Not really knowing your exact needs, I'll try to answer:

As Daysim and SPOT Pro's main difference is mainly how to treat with sun
and sky components, is that applies to all radiance-based-engine tools
(including Radiance command-line approach itself)? By other words, is the
way sun-and-sky-being-treated the main motivation to go for
radiance-based-engine-tools rather than simple tools (i.e. like Ecotect)?

The Daylight Coefficient or a Design Day interpolation annual simulation
approaches do not have to be unique to Ray-tracing engines, like Radiance.
Radiosity engines can make use of the same concepts for annual simulation.
Radiosity can often run a single point in time quicker, with other
limitations, and so can calculate more coefficients or design days. I am
not sure, but I believe Ecotect is providing an interface to Radiance for
simulation and maybe has its own sun path and solar shading design tools.

So if someone needs to just investigate how different complex fenestration
systems will affect indoor daylight coefficients (no illuminance levels nor
pictures needed), there is no need to generate BSDF data for those CFS and
even no need to use radiance?

I believe good representative BSDF data, or just a good model of the
fenestration system itself, would still be very important to get a good
calculation of daylight coefficients (which is as challenging of a
calculation as illuminance). Using Radiance based tools is not necessary
as there are other Ray-tracing and Radiosity based tools that can do
similar calculations. One convenient thing is that the Radiance based
tools use this standard XML BSDF definition now which aligns with the
Windows 7 software giving greater access to these definitions.

Regards,
Zack

···

--
Zack Rogers, P.E., LEED AP BD+C
Daylighting Innovations, LLC
808 S. Public Road, Suite 200
Lafayette, CO 80026
(303)946-2310

www.daylightinginnovations.com