Modellling light pipes / light tubes

Hi all,

I'll like to model the effect of light pipes in a two storey building.
These pipes would enter through the roof via a half-dome of glass. A
highly reflective pipe (approximately 400mm diameter) runs from this
roof to the ground floor's ceiling where it strikes a diffuser and
lights the space below.

The obvious way to model this would be a vertical cylinder with a highly
reflective surface inside. Probably the top surface (where the light
comes in) should be an illum surface. I'm not sure, however, that this
method would be very efficient or accurate.

What's the best way to model these light pipes? Has anyone done a
similar thing?

Cheers,

Brett

Brett Beeson

Sustainable Designer

CUNDALL

HSBC Building Level 20

300 Queen Street

Brisbane QLD 4000

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Brett,

You really need a forward raytracer to model light-pipes. Do this search in Google:

site:www.radiance-online.org "light pipe"

to find the previous discussions on light pipes and related.

-John

···

-----------------------------------------------
Dr. John Mardaljevic
Senior Research Fellow
Institute of Energy and Sustainable Development
De Montfort University
The Gateway
Leicester
LE1 9BH, UK
+44 (0) 116 257 7972
+44 (0) 116 257 7981 (fax)

[email protected]
http://www.iesd.dmu.ac.uk/~jm

Hi Brett,

I hesitate to suggest it, because I don't know exactly how (or even if) it would work, but the new rtcontrib program is meant to solve just this sort of problem. If you are feeling adventurous, check it out.

-Greg

···

From: "Beeson, Brett" <[email protected]>
Date: November 27, 2005 3:01:24 PM PST
Hi all,

I’ll like to model the effect of light pipes in a two storey building. These pipes would enter through the roof via a half-dome of glass. A highly reflective pipe (approximately 400mm diameter) runs from this roof to the ground floor’s ceiling where it strikes a diffuser and lights the space below.

The obvious way to model this would be a vertical cylinder with a highly reflective surface inside. Probably the top surface (where the light comes in) should be an illum surface. I’m not sure, however, that this method would be very efficient or accurate.

What’s the best way to model these light pipes? Has anyone done a similar thing?

Cheers,

Brett