[Radiance-general] Specular Reflections from Plastic?

[Baker, Kristopher]

Hello,

I have a fundamental question about Radiance that I can't figure out.  
What is the best way to get Source specular reflections from a plastic,
metal, or trans material? 

In my model, setting the specular component of the material at or near
1.0 correctly provides view reflections in the material (reflections of
the window on the other end of the room).  However, there are no
reflected solar patches, as is expected with direct sun landing on the
reflective material.

Using the material type mirror, the virtual light source is created and
the solar patch shows up, but when a plastic, metal, or trans material
is specified with a specularity at or near 1.0, there isn't even a
glimpse of the expected reflected solar patch.

As an example, imagine a window with a partition perpendicular to that
window.  The sun is out and shining through the window onto that
partition. 

-If I make that partition a mirror material type, I see this wonderful
reflected solar patch on the floor.

-If I make that partition a plastic, trans, or metal with a specular
component of 1.0, there is no reflected solar patch on the floor.

>From my understanding, the mirror treats the reflected solar patch as a
virtual light source and all is good, but it does not do this for
plastic, metal, trans.

When the plastic, metal, or trans is set as specular, Radiance
accurately shows the reflection of the view in the partition (in this
case the window), but the direct solar flux that entered and hit the
partition is gone, or at least transferred to the indirect or ambient
component. 

All parameters are defaulted at the medium level and I have bumped
direct relays to 3 (lr=6, lw=.002, dr=3, st=0.1)

This is simple and a most fundamental calculation, but alas no dice. 

Any ideas?  Thanks.


KB
Kristopher S. Baker