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<p class=MsoNormal style='margin-left:.25in'>Dear Mark and others,<o:p></o:p></p>
<p class=MsoNormal style='margin-left:.25in'><o:p> </o:p></p>
<p class=MsoNormal style='margin-left:.25in'>Interesting threat. Michael listed
a series of workflows that one can use to analyze a SketchUp scene using either
Radiance or 3ds Max Design/Mental Ray. Michael also pointed out that these two
simulation engines have been successfully validated based on measured indoor illuminances.
Before picking any of these workflows I recommend that you first carefully
decide <i>what</i> you actually want to calculate using daylight simulations.<o:p></o:p></p>
<p class=MsoNormal style='margin-left:.25in'><o:p> </o:p></p>
<p class=MsoListParagraph style='margin-left:.75in;text-indent:-.25in;
mso-list:l0 level1 lfo2'><![if !supportLists]><span style='font-family:Symbol'><span
style='mso-list:Ignore'>·<span style='font:7.0pt "Times New Roman"'>
</span></span></span><![endif]>For a <b>LEED 8.1 Daylighting Credit</b>
compliance simulation most of the work flows described by Michael should work
since the ‚old‘ CIE clear sky as well as the CIE overcast sky (for daylight
factor calculations) are supported by Radiance and 3ds Max. If this is your
objective it is worthwhile mentioning that there are many designs that fail the
LEED glazing/daylight factor requirement according to simulations but meet it
via the spreadsheet method from the LEED technical manual (see p.32: <a
href="http://www.gsd.harvard.edu/people/faculty/reinhart/documents/DiffuseDaylightingDesignSequence.pdf">www.gsd.harvard.edu/people/faculty/reinhart/documents/DiffuseDaylightingDesignSequence.pdf</a><span
style='color:#1F497D'>)</span> .<o:p></o:p></p>
<p class=MsoListParagraph style='margin-left:.75in;text-indent:-.25in;
mso-list:l0 level1 lfo2'><![if !supportLists]><span style='font-family:Symbol'><span
style='mso-list:Ignore'>·<span style='font:7.0pt "Times New Roman"'>
</span></span></span><![endif]>For <b>physically based images</b> both engines
can be used (pay attention that you actually use Mental Ray as the engine for
your 3ds Max simulations). Mental Ray tends to be faster than Radiance but
Radiance offers richer analysis capabilities including various glare indices
(if one is willing to use Radiance via the command line).<o:p></o:p></p>
<p class=MsoListParagraph style='margin-left:.75in;text-indent:-.25in;
mso-list:l0 level1 lfo2'><![if !supportLists]><span style='font-family:Symbol'><span
style='mso-list:Ignore'>·<span style='font:7.0pt "Times New Roman"'>
</span></span></span><![endif]><b>Climate-based daylighting metrics</b> have
been proposed to be superior design measures than the daylight factor (<span
lang=DE><a
href="http://irc.nrc-cnrc.gc.ca/pubs/fulltext/nrcc48669/nrcc48669.pdf"><span
lang=EN-US>http://irc.nrc-cnrc.gc.ca/pubs/fulltext/nrcc48669/nrcc48669.pdf</span></a></span>)
and IESNA and CIE are currently working on benchmark levels for these metrics.
To calculate a climate-based metric you can use Daysim, SPOT and (in principal)
even 3ds Max. The caveat for 3ds Max is that the calculations would currently
take a long time (page 29 <span lang=DE><a
href="http://www.autodesk.com/us/3dsmaxdesign/B3241.MentalRayValidation_v3.pdf"><span
lang=EN-US>www.autodesk.com/us/3dsmaxdesign/B3241.MentalRayValidation_v3.pdf</span></a></span>).<o:p></o:p></p>
<p class=MsoListParagraph style='margin-left:.75in;text-indent:-.25in;
mso-list:l0 level1 lfo2'><![if !supportLists]><span style='font-family:Symbol'><span
style='mso-list:Ignore'>·<span style='font:7.0pt "Times New Roman"'>
</span></span></span><![endif]>For <b>integrated lighting-thermal</b>
simulations one can either use a build-in method (e.g. in EnergyPlus or DOE2.1)
or link the thermal simulation program with externally calculated annual
illuminance profiles. The latter methods tends to be more accurate.<o:p></o:p></p>
<p class=MsoListParagraph style='margin-left:.25in'><o:p> </o:p></p>
<p class=MsoNormal style='margin-left:.25in'><span style='color:#4F81BD'>>>Ramana
Koti wrote: I don't think the choice of materials that can be assigned from
within SketchUp is that comprehensive yet … I'd be interested in hearing from
Christoph … when we'll be able to assign user created materials to surfaces
within SketchUp before exporting to DAYSIM.<o:p></o:p></span></p>
<p class=MsoNormal style='margin-left:.25in'>We once had a good workflow from
Sketchup 4 to Daysim via the 3ds format that allowed the user to use a
custom material library in SketchUp to automatically assign materials in
Daysim. The 3ds export file format in SketchUp 5 was unfortunately slightly
changed so that this workflow is not valid any more. I am now using Thomas
Bleicher’s earlier mentioned SketchUp to Radiance exporter. I find the only
‚hiccup‘ with this approach to be that the exporter writes out all layers into
separate files which have to be individually imported into Daysim. I also have
to manually assign the materials, i.e. there is still room for improvement.<o:p></o:p></p>
<p class=MsoNormal style='margin-left:.25in'><o:p> </o:p></p>
<p class=MsoNormal style='margin-left:.25in'>A general warning for any daylight
simulations based on a SketchUp scene is that SketchUp allows to assign
different material properties to the two surfaces of a polygon. This leaves
room for errors since Radiance only recognizes one material type per polygon.<o:p></o:p></p>
<p class=MsoNormal style='margin-left:.25in'><o:p> </o:p></p>
<p class=MsoNormal>Christoph<span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:7.5pt;font-family:"Arial","sans-serif";
color:black'>Christoph Reinhart, Dr. Ing. <o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:7.5pt;font-family:"Arial","sans-serif";
color:black'>Associate Professor of Architectural Technology</span><span
style='font-size:7.5pt;font-family:"Arial","sans-serif";color:blue'><o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:7.5pt;font-family:"Arial","sans-serif";
color:black'>Graduate School of Design - Harvard University</span><span
style='font-size:7.5pt;font-family:"Arial","sans-serif";color:blue'><o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:7.5pt;font-family:"Arial","sans-serif";
color:black'>Gund Hall 331b, 48 Quincy Street, Cambridge, MA 02138, USA</span><span
style='font-size:7.5pt;font-family:"Arial","sans-serif";color:blue'><o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:7.5pt;font-family:"Arial","sans-serif";
color:black'>t: 617 384 7269, f: 617 495 8916, </span><span style='font-size:
11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><a
href="mailto:reinhart@gsd.harvard.edu"><span style='font-size:7.5pt;font-family:
"Arial","sans-serif"'>reinhart@gsd.harvard.edu</span></a></span><span
style='font-size:7.5pt;font-family:"Arial","sans-serif";color:black'><o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal style='margin-left:.25in'><o:p> </o:p></p>
<p><o:p> </o:p></p>
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