[Radiance-general] test file

[Hu,Jia]

Thank you for clarification. Is there any material for novice
besides reference listed in this website: http://radsite.lbl.gov/radiance/?


Jia

On Sun, Jan 17, 2010 at 5:58 AM, Thomas Bleicher
<tbleicher at googlemail.com>wrote:

> Jia.
>
> See further answers within ...
>
> On Sat, Jan 16, 2010 at 4:37 PM, Hu,Jia <hujia06 at gmail.com> wrote:
> > Hello Andy:
> >
> > Sorry for my late reply. I am new for Radiance and have to learn more to
> > reply you.  Before discussing the previous question,   could I ask how I
> > can open the text editor and save as file with extension like .rad after
> I
> > install Ubuntu 9.10 because I am unfamiliar with Ubuntu (Linux)?
>
> I currently don't have an Ubuntu system installed but I think this still
> applies:
>
> > Gedit is the default Ubuntu text editor, which you can launch by clicking
> > Applications->Accessories->Text Editor on the desktop menu system.
>
> When you save files always make sure that you save in plain
> text (*.txt).
>
> > For the question in my last email, I asked that because someone
> > did some simulations before but the results seems weird. In those
> > simulations,  two identical small offices are developed with only one
> > difference. In one office, the angles of the blinds are 0 degree. For
> > another, the windows are separated into three sections (the height
> > for each section is the same). The blinds with 0 degree are also the
> > same for each section. The illuminance of the sensor points are
> > calculated for the two offices. Theoretically, the illuminance should
> > be identical or quite similar. But as I said in my last email, the
> > illuminance shows a big difference.
>
> As Andy said, without details about the rendering parameters and
> the scene/window geometry it's hard to tell why the values are so
> different. Scenes with blinds are sensitive to the right rendering
> parameters because you have to account for multiple reflections
> to achieve satisfactory results. If the scenes were rendered with
> settings that are not accurate enough you will get largely differing
> results.
>
> Another option is that the two scenes had different sky settings
> which will also result in different (absolute) illuminance values.
>
> > In addition to your explanation, is that right another possible reason is
> > the computer hardware difference. For example, one computer may calculate
> > 5+3=8, while another calculates 5+3=7.8888.  If possible,  Is there any
> test
> > file to test the accuracy of computer before running Radiance?
>
> Radiance was written to be usable on multiple platforms. There
> is a built in tolerance for rounding errors which takes care of the
> above situations. However, you can get different results (to the
> point where the calculations are untrustworthy) if you apply very
> strong optimisation options when compiling the binaries. I assume
> that you have used the binaries from the Debian/Ubuntu distribution
> provided by Bernd Zeimetz so this should not be the cause of
> your problem.
>
> There is no standard test scenario for Radiance. I think you can
> install example scenes in Ubuntu as a separate package. Some
> of these are also discussed the book "Rendering with Radiance".
>
> Once you have Radiance running (i.e. it produces images that look
> about right) it's hard to verify the accuracy because each rendering
> depends on the scene complexity and selected rendering parameters.
> Basically you have to do a set of verification renderings with changing
> settings until you have shown that your error is within a certain limit.
>
> I also used other lighting simulation apps to check that my
> results are at least in the same order of magnitude (especially
> when artificial lighting is involved).
>
> Mark Stock has written a benchmark scene which you can use
> to test your installation. It will run for a few hours, though. It renders
> a scene at high quality settings (for a picture output) and if your
> result looks like the (tiny) image on his page Radiance works fine.
>
> http://markjstock.org/pages/rad_bench.html
>
> Regards,
> Thomas
>
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