luz rasante

14:56 Dec 14, 2012 

@ Neil: You're right that the logical thing would be for lights to be in the plural (luces), but we don't know how big this space is, there could be just one recessed light (strange, but I've seen it before).

11:21 Dec 14, 2012 

I don't think that "luz" refers to light in this situation, how can something be in the direction of the light - if the lights coming through a window the direction changes along the day and throughout the year...and if it was lights it would say "luzes", wouldn't it?
I too find it hard to work out the whole sentence - that's why in my example sentence I only write a half sentence ;)
Maybe if the asker, Peter, furnished us with a few sentences before and after, the section title, etc. it would help us all a little more to help him.

10:23 Dec 14, 2012 

I think that they might have used 'rasante' to refer to the surface. Could it mean ceiling (mounted) lights? I don't think they're referring to the actual light. All the references I've seen explain the importance of installing the runners/beams in the same direction as the wiring of lighting fixtures. It's easier to reach the electrical wires above the ceiling if you work lengthwise, rather than crosswise.

09:31 Dec 14, 2012 

Pues mira que soy española y arquitecta, y me está costando entender lo que quieren decir...no está nada bien escrita la frasecita...
Tenemos dos problemas: 1) rasante se puede traducir de numerosas maneras en inglés, desde sloping hasta skimming, pasando por muchas otras. 2) luz parecería que se refiere a "span", pero podría también referirse a "light".

Siento no poderte ayudar.