How hard would it be to add IES support to Blender?
I suppose you’d need to add a new type of lamp to blender to do it properly.
You may (may, I don’t know IES much) be able to convert IES data to a texture with alpha that could be placed in front of a spotlight. If so, that could be done using python with PIL to generate images.
is there anybody who is willing to work on this?
would it be wrong to offer monnies for the dev of said ies lights ?
No, not at all, but you have to consider what you’re actually offering.
Small incentives (say, £20) tend not to attract much interest (in fact may well push some people away).
You’d have to work out exactly what you wanted, a rigid specification (implementation should do X,Y,Z, etc) and how long you thought it would take (so that the amount of money can be worked out).
I might have a go at doing a python version over the next few days (no charge, as I can’t guarantee I’d finish/it’d work), if you can provide some docs on the format, and a few examples.
Hmm that sounds like a deal! Well I am sure the Blender arch viz okes around here will greatly appreciate IES implementation in Blender.:eek:
Well I am a lightwave user, and here is what I could find on the subject so far.
Understanding IES Lights
This guy (DPONT) faked IES in LIghtwave with his plugin. You might want too ckeck it out too?
http://perso.orange.fr/dpont/plugins…s/Download.htm
http://pagesperso-orange.fr/dpont/plugins/nodes/Shadows.html
BTW do you know if Blenders Radiosity will be updated in the future to allow better GI ?
BTW
Hi my opinion is that in the future IES light will be supported by Blender. But now it is not available. I recommend you two external render engine which support IES light:
www.kerkythea.net (unbiased + photon)
www.indigorenderer.com (only unbiased)
and maybe V-ray script for Blender
Maybe In the future Blender has an internal GI engine or Yafaray will be full integrated and the IES will be supported. Just you have to wait for it and will be patient :D.
Anyway nowadays I am testing Kerkythea and I think is an very good professional render engine for accurate lighting
probably right there. patience patience…! 
Thanks for the links, I’ll try and figure out something today.
Essentially the problem is simple. Turn an IES file into a spherical map, map to icosphere, stick around light. Can’t guarantee anything, but I’ll have a whack at it.
Ok, first stage is that I now know whats going on.
http://www.kxcad.net/autodesk/3ds_max/Autodesk_3ds_Max_9_Reference/ies_standard_file_format.html
That defines the format. Should be pretty easy, with some simplifications. I recommend this reference for anyone who wants to make an IES importer properly.
Read in, write to image file. I don’t know how to do UV mapping in python, but it’s the work of a moment to do it by hand. Hopefully have something working tonight.
where is this going > ? IES where art thou ?
indigo rendrer has IES lamp i believe
and anybody knows if there is any chance of having IES curves for Blener 2.5
it would fantastic to have this and also with fluo output
it would be amazing tomput oridany lamp with their spec in blender
and see the results come out great on render
Salutations
If someone cam come up with a relatively simple formula/function/etc that takes some inputs like a lamp vector, a vector from the shaded point to the lamp, and the IES data, it should be quite simple to integrate with Blender. I can help with that, but I don’t know anything about IES and have no use for it myself, so someone else has gotta do the heavy lifting
Damn it, I dont know python! How bout I do tests ? Well cant it be faked by using a shadow map ?
the thing is that lamp will have reflection on objects wall with a certain 3D distribution of light which is basically the IES curve
so if you try to follow the instruction with indigo
it should be realtively easy but you got read the isntruction
i think that’s the easiest way to do it and fastest also
unless you got another renderer that uses the IES curve
hey let us know how it goes if you use indigo and ies curve
show us the curve you use if you have it
i’d like to try it nyself just for the fun of it
Salutations
is there kind of a diagram showing all the related angles and ditance taken into consideration in IES model
may be make a blend diagram showing it
would be interesting to see that and have a better understanding
Salutations
The angles are defined in the file, and can be completely arbitrary (though with defined start and stop points). I’m not sure of the standard model for mixing them. Something like bicubic should be fine (edit - since they will form essentially an even distribution in polar co-ordinates).
If I get up at a decent time tomorrow morning I’ll try and write something to generate a spherical map.
some have even distribution but many don’t
some have oval or more conic shape beam
so some light goes up too occasionaly
there are all kind of lamp
from fluo to filament lamp spot and many other types of fixtures
so the distribution curve is not always something evenly distributed
tha’ts why you need a model for that distribution curve
but in anycase it would be interesting to get a real lamp model in blender
hopefully in 2.5 blender coming as soon as possible
i dont know where we could suggest this for the 2.5
but if a lot of people ask for it may be will get it
Salutations
This is going from the only source I found explaining the format, so there may be other ways of storing the data but I can’t write anything for that yet. What I’m doing now would be restricted to type C goniometers (whatever that means), and is entirely based on the link I gave earlier.
I know that it can have different shape beams, but they are all based on a set of values taken in a sphere around them, so you can model the distribution by working out the spherical map. The angles themselves are evenly distributed, making it easier to interpolate between them. I think this approach would work for all the IES examples I’ve seen, but that’s not a lot
edit -
Ah, just re-read what I had written. You’re right, they aren’t even. What I meant was they aren’t completely arbitrary. They still define a grid over a sphere, but the spacing isn’t necessarily even.
ok i did not say it but i did a lot of lighting calculation with IES curves before
with some approximations but still giving and after construction checking the results
and it’s good
now i still would like a lot to see theses curves inside blender
to give it a more reall world lamp
i don’t knnow it there is way it can be done
maind you the ies curve has to be used by the renderer and not only blender
so ig uess this has to do much more with the renderer but not certain ezaCTLY WHAT IS NEEDED !
the reel lamps in blender would be a superb addition and be more realist
of the reel world!
SALUTATIONS