Photometric Formats | luxemozione

Formats photometric

Sun, September 30, 2007

In the preceding article there was talk of software to verify lighting, so I thought it might be interesting in this article describe the main types of photometric files that these programs use.
But first of all is a photometric curve (CF)? He is only two-dimensional spatial representation of the light output expressed in candelas (luminous intensity) of a lighting fixture, lighting fixture, where I intend to be a luminaire, is a source.
Each lighting fixture for each corner space emits a luminous intensity [cd], the three-dimensional representation of the intensity is called photometric solid.

Intersecting each plan get a solid two-dimensional representation of this sound and I have a different plan for each photometric curve.

From the image above you can see that the intensity at a given level (0-180 and 90-270) are described by a curve (locus of points of light intensities in fact), and in each corner I know the intensity emitted.
Normal for electrical lighting intensity is expressed in cd / klm, ie intensity expressed in candles, concerning the flow of light emitted by the source that mount, expressed in klumen (flusso/1000lm). In this way, so it becomes independent of the luminaire that mounts from the source.
But what enters photometric files? Simple photometric files contain nothing that the data needed to describe the sound of a photometric lighting body (whether source device). There are several file formats photometry:
The format or LDT EULUMDAT, officially adopted in Europe, it is a photometric dating from the early '90s, which describes the data in a unit so full estermi: symmetry, type of device, lamp type, color temperature of the source , color rendering of the source, geometry, and matrix yield photometric.
The format is very LDT categories of software used by most lighting technician (Relux, DIALux Philips calculux, etc.), that is where you need lots of data.
Format IES LM-63-95 IESNA is the official format or North America. Used by software calculation as Lightscape and 3dsMax and Viz, the format is less complete IES format LDT.
There are software downconverting the IES LDT (and not vice versa, or at least I have not known).
Board for further investigation to look at
http://www.helios32.com
for the conversion program again on helios32
http://www.helios32.com/eulumcnv.exe