[Radiance-general] Shadow above highlight?

[schwaj3 at rpi.edu]

I might agree with you, but I think if it was the window, then not only
the ceiling, but also the right and left walls would probably have dark
spots on them as well (maybe also the backwall?). It should be noted that 
the dark spot is always directly above the highlight on the floor as the
time of day changes. I don't really understand what you mean by coupling, 
but I don't believe that the shadow is related to the window, rather it
is related to the highlight on the floor. If I change the shape of the
aperture to an asymmetrical shape, such as a square with a triangle on
top, then the shadow on the ceiling seems to be a mirror image of the
highlight on the floor, rather than a projection of the window. Note that 
the two would have the triangle shape on opposite sides of the ceiling
shadow. I'm not sure if that helps answer your question.

The radiosity program I am using does not create a shadow in that
location, (or on other walls either). I believe if anything, radiosity
might simply be darker/lighter in general.

--John

==============Original message text===============
On Mon, 17 Aug 2009 13:24:46 EDT "Zack Rogers" wrote:

Hi John,

Even without this funny sampling behavior I think there could be a
slightly darker patch on the ceiling due to the 1/3 x 1/3 square on the
adjacent wall that has a 0% reflectance.  That dark portion of the
ceiling could just have a stronger coupling to the 0% reflectance surface 
than the other surfaces around.  Do your radiosity renderings show any
darker spots on the ceiling?

Cheers,
Zack


________________________________

  ZACK ROGERS, P.E., LEED AP, IESNA 
 
INTEGRATED DESIGN ASSOCIATES, INC
437 Main Street
Longmont, CO 80501
tel: 303.848.8299, fax: 303.848.8290 
www.ideasi.com 

-----Original Message-----
From: radiance-general-bounces at radiance-online.org
[mailto:radiance-general-bounces at radiance-online.org] On Behalf Of Thomas 
Bleicher
Sent: Friday, August 14, 2009 2:58 AM
To: Radiance general discussion
Subject: Re: [Radiance-general] Shadow above highlight?

On Fri, Aug 14, 2009 at 12:44 AM, Greg Ward <gregoryjward at gmail.com> wrote:
>
> Hi John,
>
> I spent a little time looking at your model, and there are some
irregularities that I'm not sure are intentional.  Specifically, I
rendered a view from the darker region of the ceiling looking down like so:

[...]

> The light patch is the one seen at the bottom of your original view,
but the dark patch below it (actually towards the camera in your first
view) is peculiar.  It appears to be an opening, where light goes but
does not return.  Was this what you meant to do?  Are you radiosity
calculations OK with this?  Infinite rays may cause some oddities in the
interpolation, which I think is at least part of what we are seeing in
the 10-20% level drop in the dark patch on the ceiling.


The dark patch should be the window opening. The ground glow has been
removed from the sky description so you look into the ...

... cold dark void. [cue flash and rolling thunder]

Thomas ;)

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