Radiance simulations maintain 200 lux minimum

Hello all,

As Greg suggested, I have posted my results to my
website. No fancy links between them, and the text
files are done as jpegs, but the info is there.

I ran simulations of a 15m x 15m room. The west wall
has 4 windows and the north, south and east walls each
have 1 central window. I simulated December 21st in
Toronto for noon, 4pm and 6pm. According to other
software and my weather data, there is no sunlight at
6pm on Dec21, and the sun is quite low, but not yet
set at 4pm. I did not model any exterior obstructions.

Using the Desktop Radiance interface in AutoCAD I
generated .rif files for the time/day selections
(Radiance>Simulation>Camera...). Then in Command
Prompt I performed RAD on the various .rif files.

The sky definitions all appear identical, except for
the time markers in the top line.
The .riff and sky.rad files are posted here:
http://www.geocities.com/cjprocha/Sky_and_Rif_files.jpg

The RAD command ran through my camera views
successfully, but generated some warnings:
warning - no light source found. Well of course, I
have no luminaires (as suggested in the Desktop
Radiance FAQ), I am studying daylighting, so I presume
I can move on despite this message.
and
warning - aiming failure for light source
"softwaretest4_38.4.2". Looking at the DesktopRadiance
FAQ, online, there would not seem to be any reason for
this warning, based on the model I have drawn. No
concave items, no cylinders, no rings with holes, etc.

The entire script for my RAD run of Dec 21 at noon is
posted here:
http://www.geocities.com/cjprocha/Rad_Script.jpg
apologies for the fuzziness.

So the resulting images are posted as follows:
December 21, noon:
http://www.geocities.com/cjprocha/Dec21_12_ca6_images.jpg
December 21, 4pm:
http://www.geocities.com/cjprocha/Dec21_16_ca6_images.jpg
December 21, 6pm:
http://www.geocities.com/cjprocha/Dec21_18_ca6_images.jpg
The false color maps are generated within the winimage
screen (Analysis>False color>choose metric,
illuminance, max=1000, intervals=10)

Note the centre of the floor of the room (roughly the
centre of the floor area as I have cast my camera
view) is near 200 lux in all three cases, even when
there are no luminaires and the scene is after
sun-set.

I've also noticed that the 6pm version produces an
ambient glow in the room, both in general and more
specifically along the ceiling edge. Where is this
light coming from?

Things I HAVE checked.
1.All planes are in contact along all edges.
2.All windows have their surface normals pointing
inwards.
3.Double and triple checked (multiple runs with same
results) each of these simulations.

I am a new user so my use of the Command Prompt to do
most of this is limited. Any suggestions would be
greatly appreciated, though.

Caroline

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