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aadravid
04-15-2006, 01:10 PM
IES LIGHTS IN 3DS MAX
by atul dravid

Introduction

IES stands for Illuminating Engineering Society. IES standard file format was created for the electronic transfer of photometric data over the web. It has been widely used by many lighting manufacturers and is one of the industry standards in photometric data distribution. An IES file is basically the measurement of distribution of light (intensity) stored in ASCII format. You can think of it as a digital profile of a real world light. In 3d software like 3ds max it can be used for creating lights with shapes and physically accurate form.


IES light files are created by many major lighting manufacturers and can be downloaded freely from their sites. One of such lighting manufacturer is Lithonia Lighting (www.lithonia.com (http://www.lithonia.com/)) which has an extensive library of IES files in different categories.


You can use an IES Viewer to view these files in a diagrammatic representation for easy understanding


http://geocities.com/aadravid/IES/IESSamples.jpg
Diagrammatic representation of different IES Lights with their Renders

There are lots of such viewers out there but I recommend the one by Andrey Legotin. It is the most well programmed IES Viewer with a Render option that shows you how a particular light would look.

http://geocities.com/aadravid/IES/IESViewer.jpg
A screenshot of an IES Viewer by Andrey Legotin


IES in 3ds max

3ds max is one of the 3d software around which supports the use of IES lights. There are two built in IES Lights in 3ds max under the Photometric Lights panel. They are IES Sun & IES Sky. IES Sun is a physically-based light object that simulates sunlight whereas IES Sky simulates atmospheric effects on skylight. For more about these two lights, you can refer to the 3ds max documentation. 3ds max also allows you to use external IES files through its Photometric Web feature. A Photometric Web is a 3D representation of the light intensity distribution of a light source. This lets you create lights with accurate intensities as per the recorded light profiles.


http://geocities.com/aadravid/IES/Samples.jpg
Same scene rendered with different IES Lights


Follow the brief tutorial below to start using IES lights in your own work.


Tutorial

This tutorial will teach you how to use IES files in your scenes. You need to have a basic understanding of 3ds max workflow and at least one IES file with you to complete this tutorial.

Create a new file or open the scene you want to put an IES light into. If you are working in a new file then create a box with inverted normals to create a sort of room for our scene. Here I have divided the box by partitions to try out different lights at once.
http://geocities.com/aadravid/IES/Tutorial01.jpg
Basic structure of the scene laid out.

To create the lights go to Create Panel, click on Lights and select Photometric from the drop-down list. You can use IES files with any of the Photometric Lights in this list except IES Sun and IES Sky. So, click on any one of the lights and put it in the scene. Place the lights properly at desired locations. I have used Target Point lights in this scene.
http://geocities.com/aadravid/IES/Tutorial02.jpg
Photometric Lights placed in all the three partitions.

Once the lights are properly placed at the desired locations, go to Modify Panel to see their Parameters. Go to the Intensity/Color/Distribution rollout and in the distribution list select ‘Web’. This is how we tell max that we want to use an external light profile file. Once you select ‘Web’ distribution, a new rollout is created called ‘Web Parameters’. In that click on the button called Web file. Browse for the IES file you want to use and select it and click Open.
http://geocities.com/aadravid/IES/Tutorial03.jpg

Once an IES file is loaded into the light, 3ds max will display its shape in the viewports. The final step is to set the intensity of the light according to your needs. You can set the intensity in lumen (lm), candela (cd) or lux (lx) or use the multiplier if you are not familiar with these units.
http://geocities.com/aadravid/IES/Result.jpg
Final Result: Without GI and with GI

END OF TUTORIAL


I hope you found this piece of information useful enough to understand IES Lights. If you have any comments, suggestions, criticisms or any information that I may have missed here then please let me know about it. Happy Lighting ;-)

-Atul Dravid aadravid@yahoo.co.in (aadravid@yahoo.co.in)

daydreameroperter
04-19-2006, 05:50 AM
hehe, you're aweomse. think you could about the same thing for using HDRI in maya?

p.s. i might jus start a new thread on it

EladDabush
04-19-2006, 11:03 AM
Thanks , this is very help full.

aadravid
04-19-2006, 05:39 PM
Thanks a lot for going through my post... I hope it helps you all in the long run! Will try to post more such articles and daydreameroperter, I will try to write something on HDRI soon! So, stay tuned!

francescaluce
04-19-2006, 06:24 PM
Hi Atul, thanks a lot for the tut. :)

can you do for me a little try in max (with and without mentalray) ?
could be also good to complete your tut.

I wanna see if GI photons spreading from a ies light in mentalray
is implemented correctly in max.
just try to shot out some photons from a gi enabled light without
using finalgathering. do the photons emitted resemble the ies
profile or the profile is not taken in account as the photons spread
in all direction ?

thanks in advance.

ciao
francesca

DoubleSupercool
04-20-2006, 04:09 AM
Hey, thanks a lot for that Atul. I am starting to get more into visualisation and while I new a bit about IES, this is really handy.

Thanks again!

stilllife27
04-21-2006, 07:21 AM
hi atul....thanks alot for the tutorial...but i will love to know more abt IES sky n sunlights n if possible can u tell us more on lighting in 3Ds Max n maya.

aadravid
04-24-2006, 08:04 PM
Hi Friends,

First of all sorry for a late reply.

francescaluce: My tutorial is a complete one as it is meant just for teaching the steps to integrate an external IES file into max and nothing more. If you have gone through the tutorial, you will also see the two final images where I have used GI in one and no GI in other. If still you have any queries about GI then you can go through a nice tutorial one of my friends posted at http://www.cgtantra.com//forum/forum_posts.asp?TID=3656&PN=1

stilllife27: All the information for using IES sky and sun lights are given extensively in the 3ds max manuals, but still I will try to brief on these soon. If you go through the manuals and still have any doubts then you can forward it to me at aadravid@yahoo.co.in

Thanks for your reply guys,
Atul Dravid

francescaluce
04-24-2006, 08:44 PM
sorry but I have any query about Gi other than the
one I asked you. and if you're loath to answer people
just don't post your 'finished' things as anyone is always
free to ask you something. lucky me I got some nice
pics from jeffpatton that illustrate what I was looking
for. :p

ciao
francesca

aadravid
04-24-2006, 08:49 PM
Good to know that you got your query solved! So, can you share the pics from jeffpatton so that we can also learn from it.

Thanks,
Atul

francescaluce
04-24-2006, 11:07 PM
atul, I repeat nice tutorial. that's it.

you don't need to understand anything from the pic
I got as it was a request to see how photons behave
in 3dsmax under lightprofiles and just because I'm
developing a shader for xsi that will have also that
feature as lightprofile in xsi are still not implemented.
technically I tried to understand if in 3dsmax and mentalray,
lightprofiles does supply also a photon emitter light shader
that take care of photons distribution based on the profile.
from the example I got from Jeff the answer seems ies (:D)
from the one I saw on the link you posted the answer seems
no. so I don't know. :)

ciao
francesca

aadravid
04-24-2006, 11:35 PM
hehehehehe... no problem bro... goodluck! :thumbsup:

NoWiSee
05-09-2006, 07:02 PM
Hi. Where can i find the most recent version of the IES Viewer?

aadravid
05-12-2006, 11:09 PM
hey NoWiSee, give me your email id and i will mail the IES Viewer to you!

hatttttieu
06-20-2006, 10:39 AM
Thanks alot for the tut.Can you mail me the ies viewer ,too? To:hatttttieu@yahoo.com.Thanks!

andronikos916
06-22-2006, 01:26 AM
Thanx for the link...and for the software tip

I will test it when have some free time...

Thanx,
Andronikos

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