Hello George,
TY for coming back to us.
The software that I am using is the Radiance Module of the IES
(APACHE) suite. This is mostly used for thermal prediction,
overheating, also compliance with local building regulation,
ventilation studies etc. The mein reason I mentioned the fact that it
was not RADIANCE or DESKTOP RADIANCE is because the data inputting
maybe (and probably is) completely different (unfortunately I have
never used RADIANCE - I am not allowed to have an old AutoCAD version
which had the add-on RADIANCE module, so don't know for sure). I do
not have a library of materials from which to choose, for example,
the "MIRROR"; instead, I assign materials/surface properties to the
wall, windows etc. Likewise, I am sure that you have your libraries,
but you can also modify them and add different/new materials, or
change the value slightly; glass manufacturers, for example, are
continuosly producing new coatings with different properties etc.

TY very much for the link, it seems to confirm that I am not 100
miles away; infact I can see, for example, that the "metal material
types" use 1.0 for full specularity and 0.5 for a "dirty" mirror.
Ideally I would need a " wavy" funtion to my specularity, but I do
not have a "METAL2" definition. No biggies, this is probably outside
the scope of my work, which is only to check DF in classrooms to see
if they comply with the reccomended guidelines.

With regards to mkillum, I think that I have seen "functions"
somewhere, but I have never used any before and I cannot check right
now (License availlability issues).

TY again,
Regards,

Willy


--- In DesktopRadiance@yahoogroups.com, "g_a_chadwick"
<g_a_chadwick@...> wrote:
>
> Hello Willy,
>
> I can't see why your approach shouldn't work apart from:- your not
> specifying what software you are using, and the interreflections
> being a problem when using many verily highly specular surfaces.
>
> So far as materials go, for mirror in Radiance I would use MIRROR
> material! Hasn't the software you use got this material? For
specular-
> reflector-lightpipe/in-lightwell I would use the mkillum program as
> the skylight source at the top as well. Doesn't the software have
> that function?
>
> Were you aware of the guidance on Radiance material types for
> Rayfront (at http://www.schorsch.com/rayfront/manual/matdef.html ),
> which uses Radiance materials formats and engines? Tis most
helpful,
> I think. As it says, a value >0.1 for specularity is 'unusual'.
Hmmm.
>
> Good luck.
>
> Regards,
> George
> <<>><<>><<>>
> --- In DesktopRadiance@yahoogroups.com, "willyfaber" <willy.pane@>
> wrote:
> >
> > Hi all,
> >
> > to start with, I am using the Radiance tool as implemented in a
> > different software suite, but I imagine that this is fairly
> > irrelevant.
> >
> > I am looking at daylight factors in classrooms using CIE uniform
> sky,
> > and at the use of light wells to "brighten up" the back of deep
> > classrooms. I want the maximum amount of light possible been
> > channeled down the light well, so I thought that some aluminium
> foil
> > coating could be used. For this coating I used the following
values:
> > R-Refl = 0.91, B-Refl = 0.92, G-Refl = 0.92 (this is roughly the
> > reflectance of polished aluminium at the different wavelength for
> > Red, Green, Blue). For specularity.... I took the average of the
3
> > values, so I used 0.917 (this is a pure guess, but I thought
that
> a
> > value of between 0.9 and 1.0 would have been appropriate - ok
maybe
> > 1.0 would have been too optimistic, so any 0.9, 0.925, 0.95 would
> > have been good). I assumed the surface to be polished, hence
> > roughness = 0.
> >
> > Is this approach valid.. or did I completely miss the point?
> > Where can I find some guidance? For example, how would I go to
> > simulate a mirror?
> >
> > many thanks,
> >
> > willy
> >
>