[Radiance-general] Re: Strange Glowing Buildings... Ack.

[Greg Ward]

Hi Jeffrey,

It sounds to me like you may have your ambient value (-av) set too 
high, or else you have ambient weighting switched on inappropriately.  
Try alternately setting -aw 0 and -av 0 0 0.

-Greg

> From: "Fitzsimmons, Rob" <Rob.Fitzsimmons at Summit.Fiserv.com>
> Date: May 27, 2004 10:52:15 AM PDT
>
Do you have a website where you can post an image? Maybe the normals 
are flipped?
I've been having perhaps a similar problem - I do most of my modeling 
in Infini-D Mac
I've modeled a buffet and there is a strange glow behind it -where it 
should more of a shadow
http://rastermon.com/Rad/Dining.htm
In the QTVR, look at the buffet (where the candelabra  and bowl are). I 
never could find out why it had that light area where it meets the 
wall. Also - the spaces between the drawers seem to glow.

Rob F

-----Original Message-----

Hello all,

        I'm having a problem with my buildings I'm exporting out of
Revit,
and am trying to figure out where the problem is coming from. I'm
hoping someone out there can help me out a little with this issue, for
I don't understand enough about Radiance to really know why this is
happening, and can only guess at why.

        Just for the record, if I make a model from scratch using
textfiles I
don't have any of these problems. Additionally, the problem crops up
whether I'm using Radiance on Cygwin, OS X, or Mandrake Linux, so it's
obviously something I'm doing or a problem with the models coming out
of Revit.

        My problem is the fact that my buildings all appear as if they
are
'glowing'. Things like the site, and any Radiance-created objects or
instances render correctly, however the buildings, especial the large
flat surfaces such as walls and such, almost appear to be glowing
because they seem to be bouncing so much light off of them, almost as
if they are made of perfect white gypsum in broad daylight.

        The material definitions for the walls aren't set too high, the
colors are typically .8 or .7 for the RGB values, and the roughness is
usually set to .15 or so- both values that don't seem too far off.
Also the Exposure for the scene tends to be about right for other
Exterior Radiance scenes and the sun is a simple Gensky straight from
the first tutorial file. Yet however the building will be bouncing
almost twice the light off of it of anything else in the scene!

        The way I get my models from Revit to Radiance might be the key
to
why the models are behaving the way they are. I export the models to a
DWG file that I then bring into AutoCAD and then use RADOUT to produce
the models. However there are issues with this, for RADOUT or TORAD
don't work quite right in the latest version of AutoCAD that I'm
using. I've tried to use dxf2rad, but it always seems to choke on the
models. They are very large, very complex, and have many surfaces. So
I'm wondering if that's the root of my problem; is something in the
export process possibly causing this?

Thanks for your time,

Jeffrey McGrew