Fw: Re: Shadow above highlight?

Here are the files and commands to run it for anyone who is interested.

  oconv -f -r 16384 sun_nosky_0621_12 p-cornell_9_quad_out.mtl

rpict -bv- -ab 1 -dp 2048 -ar 256 -ms 0.033 -ds .02 -dt .05 -dc .75 -dr 3
-sj 1 \
-vf 0.vf -st 1.0 -aa .1 -ad 2048 -as 256 -lr 24 -lw .0002 -t 60 \
sun_nosky_0621_12_hres.oct >062112-20.pic

ra_ppm -g 1 -e -2 062112-20.pic > 062112-20-t.ppm

--John Schwartz

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Can you send me your scene description, so I can have a look at it?
This is the worst possible timing for me, but you're going to get
nowhere unless you share your scene files. It's impossible to deduce
what's going wrong from an image.


From: schwaj3@rpi.edu
Date: August 13, 2009 1:42:40 PM PDT

Hmm, well no suggestions thus far has helped solve the problem I am
having. I think it would help if I explain what I am trying to do. I
attempting to validate radiosity calculations against a raytracer (in
this case Radiance). I am doing this with a simple example of a box
only by direct sun and ambient bounces, so there is no sky

I have attempted many different rendering options, such as -aa 0 and
other "high quality" level options as recommended in the Rendering
Radiance book. These do not get rid of the problem. As you can see
in my
gensky below, the sun shouldn't be approaching the zenith, as it has
revealed can cause problems.

I was reccommended to try using mkillum to turn the window into an
surface. I have attempted this, but it doesn't appear to do
anything, so
I could be using it incorrectly? I am only using a single ambient
in my calculations because the shadow is still there even on higher
amounts, such as -ab 20. I decided -ab 1 would make it easier to track
down the problem as well as take less computation time.

Any more thoughts on what could be causing this? Could it be a problem
with gensky similar to the zenith problem maybe?

--John Schwartz

From: schwaj3@rpi.edu
Date: July 27, 2009 3:41:40 PM PDT

I am fairly stumped as to what is going on here. I have a box with a
square hole, 1/3 x 1/3 the width of the box, to allow sunlight into
my room.

I am using the following gensky to attempt to only light the room
!gensky 6 21 12:00EST -a 40.77 -o 73.967 -g 0.0 +s
skyfunc glow sky_glow
4 0 0 0 0

sky_glow source sky
4 0 0 1 180

This picture was rendered using -ab 1
http://i639.photobucket.com/albums/uu111/radiancebox/radiance.jpg> >> You'll note on this image, that there is a strange shadow on the > >> ceiling.
I am unable to figure out why.

If I instead place a light in the room, also 1/3x 1/3 the size of the
box, I do not have this problem. This picture is taken from the
"back" of
the box, with the light on the ceiling instead of the floor. There
is no
gensky used on this picture.

http://i639.photobucket.com/albums/uu111/radiancebox/Light.jpg >> This > picture was rendered using -ab 0>>> Changing the camera angle doesn't effect the shadow seen in the first
picture. I have determined that the shape of the window is not
the shadow, instead the highlight on the floor causes the shadow on

If anyone can help clear this up for me, I would appreciate it.


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Sketchup2Radiance.rad (979 Bytes)

sun_nosky_0621 (637 Bytes)

p-cornell_9_quad_out.rad (13.8 KB)

p-cornell_9_quad_out.mtl (128 Bytes)

0.vf (101 Bytes)


On Thu, 13 Aug 2009 16:58:44 EDT Greg Ward wrote: