Russell,
We have successfully modelled the refractive light redirection system
known as the ‘laser cut panel’. It is simply a sheet of acrylic
with laser cuts in it. The cuts redirect incident illumination by
total internal reflection, giving the panel very powerful light
redirecting properties. The algorithm to model the device is based
on some simple geometrical calculations of directions of deflected and
undeflected rays, and relative intensities of the rays. The
modifier used is the prism2 material. For more info, check the
paper in Lighting Research and Technology:
Greenup, P.J., Edmonds, I.R. and Compagnon, R. (2000), Radiance
Algorithm to Simulate Laser-Cut Panel Light-Redirecting Elements,Lighting Research and Technology, 32 (2), 49-54.
I have also developed some algorithms to model reflecting light
redirecting devices, known as light guiding shade panels. The
process is:
model the flat reflective surfaces as polygons, the curved reflective
surfaces using gensurf
run oconv with the appropriate room and sky definitions
set a void output surface adjacent to the inside of the light redirecting
device
run mkillum with appropriately high settings of the -s and -d parameters
in particular
add the resulting geometry using oconv -i …
get your pictures, illuminances, etc as usual.
the results for each algorithm have been compared against measurements in
labs and in test buildings, and compare well. if you would like
more info, or the calculation file for the laser cut panels, let me know
and i will be happy to send it to you.
Regards,
Phil Greenup
On a side note I am also looking at modelling
light redirection systems (horizantal/vertical
glazing) and refractive systems. I have looked at some of the designs on
www.schorsch.com
and attempted to model them using AutoCAD or a gen program then assigning
a dielectric
material. Does any else have experience with creating these and would it
be possible
to use a different modifier? I am looking for the most accurate
calculation.
Thanks
Russell Maunder
BBSc (hons)
Victoria University of Wellington
School of Architecture and Design
New Zealand
Phil Greenup
Centre for Medical, Health and Environmental Physics
Queensland University of Technology
GPO Box 2434
Brisbane Qld 4001 Australia
Ph (07) 3864 5362
Fax (07) 3864 9079
Email [email protected]