[Radiance-general] mirror material ignoring modifier in virtual source calculations

[goodriver laurus]

Greg,

I think I may have found the issue. I was creating a simpler scene to send
over when I realized that the angular dependence was actually working. I
almost missed it because the differences were small, but it was working.
So, I went back to the original test and I discovered that the difference
was that I had been using aliases in the original test, but had had not
used them in the simplified scene I sent you, sorry about that. Could that
be it?

When I use aliases the mirror material seems to ignore the modifier:

void glass glass_alt_mat
0
0
3 0.96 0.96 0.96

void brightfunc glass_angular_effect
2 A1+(1-A1)*(exp(-5.85*Rdot)-0.00287989916) .
0
1 0.08

glass_angular_effect mirror glass_mat
1 glass_alt_mat
0
3 1 1 1
void  alias window glass_mat

If I use 'window' as the material for the geometry, then 'glass_mat' alias
is used instead, but the 'glass_angular_effect' modifier seems to be
ignored. However, if I apply 'glass_mat' as the material for the geometry
then it does work. So, I wonder if this is a reasonable explanation and if
it can be explained by the work aliases work. If that is the case it would
be great to know if there is a way around it so I can keep using aliases
whilst making sure modifiers are not ignored.

Many thanks,

Rioboo

Hi Rioboo,

Your bat file only creates a single rendering with a single solar
position.  In fact, I don't understand the output, which looks much
darker than it should be for direct solar illumination.  Are you
rendering different solar angles?  Can you do it with a simpler test
case, like a single piece of glass with your mirror parallel to a
diffuse surface that does not face the sun?  If you ran that at
different solar incident angles, the value divided by the cosine of
the incident angle (to account for grazing sunlight) should follow the
Fresnel approximation you are using.

Cheers,
-Greg
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.radiance-online.org/pipermail/radiance-general/attachments/20160614/77b1489b/attachment.html>