[Radiance-general] Redirecting+scattering

[Federico Giovannetti]

Hallo Greg Ward, hallo Radiance Community!

I've been learning Radiance for a couple of weeks and i have to work intensively with it in the next weeks, as I´m investigating the energy saving potential and visual comfort of systems combining angular selective and diffusing panes.

Now I have to simulate a simple test-room with a complex fenestration, which includes an exterior prismatic structure as shading device and a diffusing pane for glare control. I try to find out the best way to model the system so as to get quantitative accurate results (RwR Chapters 10-13 and mails archive) but i´m still a little bit confused....

- As to the prismatic structure, i will use the PRISM2 material as virtual source. No redirection of diffuse incoming light and no dispersion are the only limitations of this material. And it would make no sense to use the PhotoMap port, because these materials are not implemented in this tool.  Is it right?

- As to the diffuser, i would intuitively treat it as an ILLUM with a BRTDF function as alternate material (I´m measuring, modelling and comparing different kind of diffusers) and run  MKILLUM.  If i understood correctly, the BRTDF materials are only considered in the direct calculation and indirect specular, but not in the indirect diffuse, where they are approssimate to lambertian diffusers. Should i try another material?

- How are PRISM materials computed in the MKILLUM calculation of the window light output? Should I better try to run the simulation without MKILLUM and high ambient parameters (-ab, -ad, -as)?

- What if i measure the BRTDF of the complete system and i model it as a normal light source? It is really difficult (or impossible) to get sharp peaks in light output with  high subsampling and jittering of the source? 

Any other suggestion to simulate this system correctly (quantitative)? 

Sorry for so many questions and THANKS A LOT for any contribution.

Regards,
Federico Giovannetti

---------------------------------------------------------
Federico Giovannetti
Institut für Solarenergieforschung GmbH
Am Ohrberg 1
D-31860 Emmerthal

tel:        +49(0)5151-999-501
fax:       +49(0)5151-999-500
e-mail:   f.giovannetti at isfh.de
internet: www.isfh.de
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://radiance-online.org/pipermail/radiance-general/attachments/20050519/29880a28/attachment.htm