lighting fixtures data

radiance-general
1

Hi there

I've been trawling the internet for a while now looking for ies data files (or any other standard fot that matter) for theatrical lighting instruments, with out any luck at all.

I've found lots of data architecturial lanterns, and lots for the actual bulbs (from ge, osram etc)but these aren't very useful when you're trying to light a theatre, with the lanterns that are available there.

The only best photometric data i've found is from ETC:

http://www.etcconnect.com/docs_downloads/datashts/S4_19_Deg_vD.pdf

where they give you a "Candlepower Distribution Curve" as well as field and beam angles, but most places dont even give that.

I also have the problem that most of the lanterns i'm interested in are focusable, and many are zoomable as well, so i need data at a couple of focus/zoom settings (i can then interpolate between these).

Does anyone have any ies (or other useful format, or even radiance format) files about any theatrical lanterns? ideally i'm after selecon lanterns, but i would be happy with some generic data for the standard lantern types:
-profiles (of various angles)
-fresnels
-pc's (less important)
prerferably data at a couple of focus settings, and data for 1kW and 500W lanterns.

I dont have access to the facilities to make my own measurements, and i can't figure out how to use the data provided (http://www.seleconlight.com/english/support/english/acclaim%20fresnel.pdf for the selcon fresnel i'm particulary interested in) to estimate the figures.

So if anyone can come up with any advice, or has any suggestions of where I can get hold of this data it would be very much appreciated.
[I will be using the data in part of an undergraduate engineerig degree project, and wont use anythign for any commercial purposes if it makes any difference to anyone].

Thanks for your help everyone
will

2

Hi WIll,

Funny you should mention this, because here I find myself attending Rob Shakespeare's "Virtual Scenography in Live Performance" symposium at Indiana University <http://www.indiana.edu/~vslp/&gt;, where a bunch of theater types and researchers are gathered talking about lighting, simulation, and the like.

I will definitely ask Rob if he has any data, and maybe he'll respond with some pointers as well. Are you planning to input this directly into Radiance, or do you have other tools in mind as well? (I.e., do you need IES format data, or can you get by with something not easily converted to IES?)

The reason I ask is that I've been toying with HDR imaging as a quick and convenient method to get at certain types of photometry, where the projection angle is small but the pattern potentially complex -- i.e., theater lighting instruments. The method is simple, but there are a few details to work out. Basically, you set your instrument and point it at a blank wall or ceiling or some diffuse, white surface large enough to encompass the beam. Then, you take an HDR photograph of the beam pattern. The part I haven't worked out completely is using this as input to Radiance, but if you have some basic distance and beam size measurements, this should be straightforward.

You would of course need a reasonable digital camera -- SLRs are generally better due to the better flare characteristics of their lenses, and access to the light instrument of interest and a dark room to do the measurements. If this is of interest, I would be happy to help you assemble an example photometric distribution as a proof of concept.

-Greg

···

From: william reynolds <[email protected]>
Date: March 3, 2006 6:55:37 AM EST

Hi there

I've been trawling the internet for a while now looking for ies data files (or any other standard fot that matter) for theatrical lighting instruments, with out any luck at all.

I've found lots of data architecturial lanterns, and lots for the actual bulbs (from ge, osram etc)but these aren't very useful when you're trying to light a theatre, with the lanterns that are available there.

The only best photometric data i've found is from ETC:

http://www.etcconnect.com/docs_downloads/datashts/S4_19_Deg_vD.pdf

where they give you a "Candlepower Distribution Curve" as well as field and beam angles, but most places dont even give that.

I also have the problem that most of the lanterns i'm interested in are focusable, and many are zoomable as well, so i need data at a couple of focus/zoom settings (i can then interpolate between these).

Does anyone have any ies (or other useful format, or even radiance format) files about any theatrical lanterns? ideally i'm after selecon lanterns, but i would be happy with some generic data for the standard lantern types:
-profiles (of various angles)
-fresnels
-pc's (less important)
prerferably data at a couple of focus settings, and data for 1kW and 500W lanterns.

I dont have access to the facilities to make my own measurements, and i can't figure out how to use the data provided (http://www.seleconlight.com/english/support/english/acclaim%20fresnel.pdf for the selcon fresnel i'm particulary interested in) to estimate the figures.

So if anyone can come up with any advice, or has any suggestions of where I can get hold of this data it would be very much appreciated.
[I will be using the data in part of an undergraduate engineerig degree project, and wont use anythign for any commercial purposes if it makes any difference to anyone].

Thanks for your help everyone
will

3

Greg
Good timing 'eh!
I was hoping to find IES data, but I have heard of EULUMDAT -> IES converter somewhere, so that would be possible too. failing that, i figured anything was better than nothing, and i'd work out how use the data once i got it if it was a different format!

the HDR idea sounds really interesting though. unfortunately i know nothing about it as yet, but i'll try google as my next step!
Any help you could give me would be really appreciated - this input method sounds very helpful as i do have access to the lights, a dark room and a camera!

I dont quite understand how you would get the data into radiance though - the only idea I can think of at he moment would be to somehow convert the pixel brightness information into a .dat file that you then used with a source as normal. So I guess you would need to turn the photo into .pic file, and then somehow extract the pixel brightness data into another file and interpret it, perhaps converting it to ies format? or even stright to .dat?

am i wildly out, or somehow along the right lines. i'm thinking on my feet, and there my well allready be something with in radiance to do all this!

thanks for the suggestion. off to look up HDR now!
will

Gregory J. Ward wrote:

···

Hi Will,

Funny you should mention this, because here I find myself attending Rob Shakespeare's "Virtual Scenography in Live Performance" symposium at Indiana University <http://www.indiana.edu/~vslp/&gt;, where a bunch of theater types and researchers are gathered talking about lighting, simulation, and the like.

I will definitely ask Rob if he has any data, and maybe he'll respond with some pointers as well. Are you planning to input this directly into Radiance, or do you have other tools in mind as well? (I.e., do you need IES format data, or can you get by with something not easily converted to IES?)

The reason I ask is that I've been toying with HDR imaging as a quick and convenient method to get at certain types of photometry, where the projection angle is small but the pattern potentially complex -- i.e., theater lighting instruments. The method is simple, but there are a few details to work out. Basically, you set your instrument and point it at a blank wall or ceiling or some diffuse, white surface large enough to encompass the beam. Then, you take an HDR photograph of the beam pattern. The part I haven't worked out completely is using this as input to Radiance, but if you have some basic distance and beam size measurements, this should be straightforward.

You would of course need a reasonable digital camera -- SLRs are generally better due to the better flare characteristics of their lenses, and access to the light instrument of interest and a dark room to do the measurements. If this is of interest, I would be happy to help you assemble an example photometric distribution as a proof of concept.

-Greg

From: william reynolds <[email protected]>
Date: March 3, 2006 6:55:37 AM EST

Hi there

I've been trawling the internet for a while now looking for ies data files (or any other standard fot that matter) for theatrical lighting instruments, with out any luck at all.

I've found lots of data architecturial lanterns, and lots for the actual bulbs (from ge, osram etc)but these aren't very useful when you're trying to light a theatre, with the lanterns that are available there.

The only best photometric data i've found is from ETC:

http://www.etcconnect.com/docs_downloads/datashts/S4_19_Deg_vD.pdf

where they give you a "Candlepower Distribution Curve" as well as field and beam angles, but most places dont even give that.

I also have the problem that most of the lanterns i'm interested in are focusable, and many are zoomable as well, so i need data at a couple of focus/zoom settings (i can then interpolate between these).

Does anyone have any ies (or other useful format, or even radiance format) files about any theatrical lanterns? ideally i'm after selecon lanterns, but i would be happy with some generic data for the standard lantern types:
-profiles (of various angles)
-fresnels
-pc's (less important)
prerferably data at a couple of focus settings, and data for 1kW and 500W lanterns.

I dont have access to the facilities to make my own measurements, and i can't figure out how to use the data provided (http:// www.seleconlight.com/english/support/english/acclaim%20fresnel.pdf for the selcon fresnel i'm particulary interested in) to estimate the figures.

So if anyone can come up with any advice, or has any suggestions of where I can get hold of this data it would be very much appreciated.
[I will be using the data in part of an undergraduate engineerig degree project, and wont use anythign for any commercial purposes if it makes any difference to anyone].

Thanks for your help everyone
will

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

4

From: william reynolds <[email protected]>
Date: March 3, 2006 8:01:21 AM EST

...
I dont quite understand how you would get the data into radiance though - the only idea I can think of at he moment would be to somehow convert the pixel brightness information into a .dat file that you then used with a source as normal. So I guess you would need to turn the photo into .pic file, and then somehow extract the pixel brightness data into another file and interpret it, perhaps converting it to ies format? or even stright to .dat?

am i wildly out, or somehow along the right lines. i'm thinking on my feet, and there my well allready be something with in radiance to do all this!

It's even simpler, since you can use a Radiance .pic file (a.k.a. an HDR image) in a colorpict primitive with a simple coordinate mapping to get the output distribution directly. This takes less memory and less file space than converting it to a .dat file, with no loss in accuracy.

For more info on HDR, check out the HDRI list on www.radiance-online.org.

-Greg

5

Good timing indeed! I am working on a luminaire database for
brad and was looking for the converters a few days ago:

One (DOS) is available here (link at the bottom of the page):

http://www.helios32.com/resources.htm#Formats

And Carsten Bauer has another one for Linux/Unix:

http://www.cb-d.de/rzgoodies.html

BTW: Is any one on this list in the situation (read: in possession of
      and allowed to) to share file format specs for the IES 2002 and
      Eulumdat/2 data files? I've only a description of the 1995 version
      of IES and the first Eulumdat version and my database could use the
      additional information in the new files.

Thomas

···

On 03.03.2006, at 14:01, william reynolds wrote:

Greg
Good timing 'eh!

I was hoping to find IES data, but I have heard of EULUMDAT -> IES
converter somewhere, so that would be possible too.

6

Hi there

Hi William...

I've been trawling the internet for a while now looking for ies data files (or any other standard fot that matter) for theatrical lighting instruments, with out any luck at all.

Yeah, you found the best data already at ETC. Rob Shakespeare definitely has some data but I don't think he's ever distributed it. (Greg, see what you can do; that symposium sounds really interesting.) A detailed process for obtaining datasets for theatrical fixtures, including sharp & soft focus, is presented (again by Rob S.) in the Rendering with Radiance text. I know you said you don't have facility access to make these measurements, but I thought you'd find it interesting nonetheless.

If you need color filter info, I have a spreadsheet that lists the rgb values for the Roscolux color filter line. Rob S may have something similar. I got mine from a guy at ETC a few years ago, but must admit I have not used it at all (one of many back burner projects), and can't vouch for its validity.

Thomas, sorry; the only electronic info I have on the ies format is from Ian Ashdown,s great paper "Thinking Photometrically" -- actually coursenotes froma lecture he did a number of years ago -- and this details the earlier format. I do own a copy of the latest spec (LM-63-02), so if there are any specific questions you had, I may be able to answer them.

- Rob

···

On Mar 3, 2006, at 4:55 AM, william reynolds wrote:

7

Thomas, sorry; the only electronic info I have on the ies format
is from Ian Ashdown,s great paper "Thinking Photometrically" --
actually coursenotes froma lecture he did a number of years ago
-- and this details the earlier format.

That's my resource for the old formats, too.

I do own a copy of the latest spec (LM-63-02), so if there are any
specific questions you had, I may be able to answer them.

I've found that the definition of shapes has changed from
95 to 2002. Shapes are "encoded" as negative dimensions in
x,y,z. If you could compare how this is done now or how the
shapes are "encoded" in 2002 vs. 95 this would be a great
help. That's the only place where I fear that the new standard
could be interpreted wrong. Everything else is just a more
strict interpretation of old rules AFAIK.

BTW: It's the same for EULUMDAT/2: They just squeeze more
      information into an already existing field. If you don't
      know about it you get funny names for the manufacturer
      and the report; But that's all.

TIA,

Thomas

···

On 03.03.2006, at 20:29, Rob Guglielmetti wrote:

8

hi everyone
i've been trying out this hdr stuff, and i've run into a bit of a dead end with my understanding!

i've left this on the general list, as it seems a slightly more general use of hdr imaging. correct me if im wrong!

i've tried what you suggested greg, using an image i found (its not hdr, thoug i converted it to .pic) rather than a photo of the real lantern i want to use (hopefully i'll be able to go in and take some photos early in the week). but the images i can generate are turning out a bit messy - i wasn't sure that its just noise because the patteern seems very regular, and there are 2 sorts of "mess" on the image as well. i've put my files up at http://users.ox.ac.uk/~orie1226/rad/ if someone wouldn't mind having a quick look at what i've done. (files.txt explains what everything is).

basically i've used the image to define the output distribution of a source, and am then using that to light a room. the likely problems seem to me to be either:
-some badly set arguments in my .rif file (i dont feel like i completely know what im doing, so this seems quite possible!), or
-a problem with the quality of the image im using to describe the source distribution. it's not that good quality, but i didn't think it was that bad.

also, all i've been able to find about using hdr images in rendering is about using an image showing the light distbution across a whole scene so that a entire scene can be lit by a single, large sperhical source surrounding it. (at least, i think thats the idea!).
what im trying to do is define the complete output of source as i'm trying to model the effect of different combinations of sources on my scene. does anyone know of any literature out there that might be relevant to this (i think simpler) approach?

thanks for your help.
will

Gregory J. Ward wrote:

···

From: william reynolds <[email protected]>
Date: March 3, 2006 8:01:21 AM EST

...
I dont quite understand how you would get the data into radiance though - the only idea I can think of at he moment would be to somehow convert the pixel brightness information into a .dat file that you then used with a source as normal. So I guess you would need to turn the photo into .pic file, and then somehow extract the pixel brightness data into another file and interpret it, perhaps converting it to ies format? or even stright to .dat?

am i wildly out, or somehow along the right lines. i'm thinking on my feet, and there my well allready be something with in radiance to do all this!

It's even simpler, since you can use a Radiance .pic file (a.k.a. an HDR image) in a colorpict primitive with a simple coordinate mapping to get the output distribution directly. This takes less memory and less file space than converting it to a .dat file, with no loss in accuracy.

For more info on HDR, check out the HDRI list on www.radiance- online.org.

-Greg

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

9

Hi Will,

I think your problem is in "source_pic.cal":

mr(r,g,b) = r;
mg(r,g,b) = g;
mb(r,g,b) = b;

myu = Px/128;
myv = Px/128;

First off, you are using Px as indices for both u and v picture coordinates, which is bound to be wrong. Second, you should probably be using something based on the ray direction rather than the intersection point, which is with the light source surface and unrelated to the output distribution. Something more along the lines of:

myu = atan2(-Dx, Dz)/(20*DEGREE) + 0.5;
myv = atan2(Dy, Dz)/(20*DEGREE) + 0.5;

The above assumes that your light is pointed in the negative Z direction (as it seems to be) and that your distribution is oriented with the horizontal scanlines along the X-axis in world space. It also assumes that the picture is square and covers 20 degrees horizontally and vertically.

A paper that covers this idea in great detail, including local photometry modelling, is:

  M. Goesele, X. Granier, W. Heidrich, and H.-P. Seidel
  "Accurate Light Source Acquisition and Rendering"
  SIGGRAPH '03
  <http://www.cs.ubc.ca/~heidrich/Papers/Siggraph.03.pdf&gt;

-Greg

···

From: william reynolds <[email protected]>
Date: March 5, 2006 5:54:03 AM PST

hi everyone
i've been trying out this hdr stuff, and i've run into a bit of a dead end with my understanding!

i've left this on the general list, as it seems a slightly more general use of hdr imaging. correct me if im wrong!

i've tried what you suggested greg, using an image i found (its not hdr, thoug i converted it to .pic) rather than a photo of the real lantern i want to use (hopefully i'll be able to go in and take some photos early in the week). but the images i can generate are turning out a bit messy - i wasn't sure that its just noise because the patteern seems very regular, and there are 2 sorts of "mess" on the image as well. i've put my files up at http://users.ox.ac.uk/~orie1226/rad/ if someone wouldn't mind having a quick look at what i've done. (files.txt explains what everything is).

basically i've used the image to define the output distribution of a source, and am then using that to light a room. the likely problems seem to me to be either:
-some badly set arguments in my .rif file (i dont feel like i completely know what im doing, so this seems quite possible!), or
-a problem with the quality of the image im using to describe the source distribution. it's not that good quality, but i didn't think it was that bad.

also, all i've been able to find about using hdr images in rendering is about using an image showing the light distbution across a whole scene so that a entire scene can be lit by a single, large sperhical source surrounding it. (at least, i think thats the idea!).
what im trying to do is define the complete output of source as i'm trying to model the effect of different combinations of sources on my scene. does anyone know of any literature out there that might be relevant to this (i think simpler) approach?

thanks for your help.
will

10

greg
thanks for the suggestion for the mapping.
i'm afraid i dont quite understand it though!

i've put a rendering up at http://users.ox.ac.uk/~orie1226/rad/ again. its called lantern_2.2.pic (or .jpg) using your suggestions for the .cal file. it seems to go a bit strange though, making a sort of star pattern!

the idea seems right - that the brightness of a ray is dependant on the angle to the normal of the source (rather than on the point it leaves the source from, as i originally had), but i'm lost with the idea of a square picture covering 20 degrees! what does this mean?

please could you also explin the bit of code you gave? particularly the divisor, and why there is an offset. also, what does the DEGREE word do? i guess its a constant - perhaps to convert deg -> radians?

thanks very much
will

Greg Ward wrote:

···

Hi Will,

I think your problem is in "source_pic.cal":

mr(r,g,b) = r;
mg(r,g,b) = g;
mb(r,g,b) = b;

myu = Px/128;
myv = Px/128;

First off, you are using Px as indices for both u and v picture coordinates, which is bound to be wrong. Second, you should probably be using something based on the ray direction rather than the intersection point, which is with the light source surface and unrelated to the output distribution. Something more along the lines of:

myu = atan2(-Dx, Dz)/(20*DEGREE) + 0.5;
myv = atan2(Dy, Dz)/(20*DEGREE) + 0.5;

The above assumes that your light is pointed in the negative Z direction (as it seems to be) and that your distribution is oriented with the horizontal scanlines along the X-axis in world space. It also assumes that the picture is square and covers 20 degrees horizontally and vertically.

A paper that covers this idea in great detail, including local photometry modelling, is:

    M. Goesele, X. Granier, W. Heidrich, and H.-P. Seidel
    "Accurate Light Source Acquisition and Rendering"
    SIGGRAPH '03
    <http://www.cs.ubc.ca/~heidrich/Papers/Siggraph.03.pdf&gt;

-Greg

From: william reynolds <[email protected]>
Date: March 5, 2006 5:54:03 AM PST

hi everyone
i've been trying out this hdr stuff, and i've run into a bit of a dead end with my understanding!

i've left this on the general list, as it seems a slightly more general use of hdr imaging. correct me if im wrong!

i've tried what you suggested greg, using an image i found (its not hdr, thoug i converted it to .pic) rather than a photo of the real lantern i want to use (hopefully i'll be able to go in and take some photos early in the week). but the images i can generate are turning out a bit messy - i wasn't sure that its just noise because the patteern seems very regular, and there are 2 sorts of "mess" on the image as well. i've put my files up at http://users.ox.ac.uk/ ~orie1226/rad/ if someone wouldn't mind having a quick look at what i've done. (files.txt explains what everything is).

basically i've used the image to define the output distribution of a source, and am then using that to light a room. the likely problems seem to me to be either:
-some badly set arguments in my .rif file (i dont feel like i completely know what im doing, so this seems quite possible!), or
-a problem with the quality of the image im using to describe the source distribution. it's not that good quality, but i didn't think it was that bad.

also, all i've been able to find about using hdr images in rendering is about using an image showing the light distbution across a whole scene so that a entire scene can be lit by a single, large sperhical source surrounding it. (at least, i think thats the idea!).
what im trying to do is define the complete output of source as i'm trying to model the effect of different combinations of sources on my scene. does anyone know of any literature out there that might be relevant to this (i think simpler) approach?

thanks for your help.
will

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

11

Hi Will,

I don't really have time here to offer a complete tutorial on Radiance .cal files. There's Chapter 4 of RwR and some useful information in <http://radsite.lbl.gov/radiance/refer/filefmts.pdf&gt;\.

Your results are actually OK. If you reduce the exposure, you'll see that your source pattern is coming through. The odd streaks at the edges are due to the fact that you have no cut-off in your fixture, but the distribution data is not quite zero at the edges. Radiance is extrapolating the distribution function, which is a bad idea in this case.

-Greg

From: william reynolds <[email protected]>
Date: March 6, 2006 7:01:41 AM PST

greg
thanks for the suggestion for the mapping.
i'm afraid i dont quite understand it though!

i've put a rendering up at http://users.ox.ac.uk/~orie1226/rad/ again. its called lantern_2.2.pic (or .jpg) using your suggestions for the .cal file. it seems to go a bit strange though, making a sort of star pattern!

the idea seems right - that the brightness of a ray is dependant on the angle to the normal of the source (rather than on the point it leaves the source from, as i originally had), but i'm lost with the idea of a square picture covering 20 degrees! what does this mean?

It covers 20 degrees horizontally and vertically, and proportionally more than 20 degrees diagonally.

please could you also explin the bit of code you gave? particularly the divisor, and why there is an offset. also, what does the DEGREE word do? i guess its a constant - perhaps to convert deg -> radians?

Actually, it's radiance -> degrees.

···

thanks very much
will

12

Thomas Bleicher wrote:

I've found that the definition of shapes has changed from
95 to 2002. Shapes are "encoded" as negative dimensions in
x,y,z. If you could compare how this is done now or how the
shapes are "encoded" in 2002 vs. 95 this would be a great
help. That's the only place where I fear that the new standard
could be interpreted wrong. Everything else is just a more
strict interpretation of old rules AFAIK.

Hi Thomas,

I believe everything you're looking for is in "annex D" of the new LM-63. I have scanned those two pages and attached them here. Hope these help!

- Rob

13

Rob Guglielmetti wrote:

Hi Thomas,

I believe everything you're looking for is in "annex D" of the new LM-63. I have scanned those two pages and attached them here. Hope these help!

OK, I think I need coffee. (Not only was the email sent to the wrong recipient, but the attachments were omitted as well. Nice. Sorry, list. Thomas, your attachments are on the way in a separate, off-list email.)