Reality and IES

User avatar
sigstan
Posts: 416
Joined: Sat Jan 24, 2015 3:59 pm
Location: Denmark

Reality and IES

Postby sigstan » Mon Dec 12, 2016 4:09 pm

I have been tinkering a bit with IES profiles for mesh lights in Reality and thought I might might share a short tutorial on this.

An IES file is the measurement of distribution of light (intensity) stored in ASCII format. IES profiles are useful for creating life-like lighting, as they can represent the physical distribution of light from any light source.

Here is an example of lights with different IES profiles (From Maya Zest free IES files):
iesguide.jpg

Any of these profiles can be attached to a mesh light in Reality and this will make the light behave according to the IES profile. Yes, that means you can turn a little mesh light plane into a round spot light with a well-defined light cone!

IES profiles makes is possible to control the light cones and light spill to a degree that is not possible using standard mesh lights and it will take your renders to the next level.

In the tutorial I show how to make a rather simplistic (primitive-only) simulation of a flashlight in a otherwise low-light scene with a bunch of low-emissive light sources. All to demonstrate the amount of control you can achieve with IES profiles:
FlashLight.jpg

As a bonus I also show how to create the in-air visible light beam shown above using a render effective localized fog/dust volume.

Finally, it contains links to free IES resources and some great tools to view and generate IES profiles.

You can grab the tutorial here:
Reality_and_IES_v1_2.pdf
(830.23 KiB) Downloaded 85 times

Hope you find it useful and let me know, if you have any questions or find any errors.

Enjoy!

Edit:
Updated with better quality PDF.
Updated Dropbox links
Last edited by sigstan on Mon Sep 11, 2017 2:32 pm, edited 7 times in total.
/Sigstan

pciccone
Site Admin
Posts: 1720
Joined: Mon Feb 25, 2013 6:25 pm

Re: Reality and IES

Postby pciccone » Mon Dec 12, 2016 5:38 pm

Thank you very much Niels. Great resource.
--
Paolo

User avatar
sigstan
Posts: 416
Joined: Sat Jan 24, 2015 3:59 pm
Location: Denmark

Re: Reality and IES

Postby sigstan » Mon Dec 12, 2016 5:48 pm

pciccone wrote:Thank you very much Niels. Great resource.

Thanks, Paolo.
/Sigstan

User avatar
Kimberly58
Posts: 206
Joined: Sun Apr 27, 2014 12:52 am

Re: Reality and IES

Postby Kimberly58 » Thu Dec 15, 2016 7:54 am

This is just awesome! Thank you so much!

User avatar
Marcel2586
Posts: 413
Joined: Sat Mar 05, 2016 7:42 am

Re: Reality and IES

Postby Marcel2586 » Thu Dec 15, 2016 9:27 am

Thank you Niels, wonderful tutorial.
this would be funny if it weren't happening to me :shock:

User avatar
sigstan
Posts: 416
Joined: Sat Jan 24, 2015 3:59 pm
Location: Denmark

Re: Reality and IES

Postby sigstan » Thu Dec 15, 2016 2:29 pm

Kimberly58 wrote:This is just awesome! Thank you so much!


Marcel2586 wrote:Thank you Niels, wonderful tutorial.


Thanks, both of you. Happy that you find it useful.
/Sigstan

User avatar
Marcel2586
Posts: 413
Joined: Sat Mar 05, 2016 7:42 am

Re: Reality and IES

Postby Marcel2586 » Fri Mar 24, 2017 11:21 am

any idea why i get this message Sigstan?
[2017-03-24 16:29:44 Warning: 4] Invalid IES file: C:/Users/Marcel/Downloads/IES_profiles/SoftDisplay.ies
i tried all kinds of IES profiles from the internet and all the same error.
this would be funny if it weren't happening to me :shock:

User avatar
sigstan
Posts: 416
Joined: Sat Jan 24, 2015 3:59 pm
Location: Denmark

Re: Reality and IES

Postby sigstan » Fri Mar 24, 2017 2:57 pm

Marcel2586 wrote:any idea why i get this message Sigstan?
[2017-03-24 16:29:44 Warning: 4] Invalid IES file: C:/Users/Marcel/Downloads/IES_profiles/SoftDisplay.ies
i tried all kinds of IES profiles from the internet and all the same error.

There are a lot of IES files out there which do not follow the standard format and Luxrender IES parser is pretty strict.

Most errors seem to be due to the file missing a mandatory keyword. The initial part of a normal IES file will look something like this:
IESNA:LM-63-1995
[TEST]BALLABS TEST NO. 13700.0
[MANUFAC] INFINITY LIGHTING INC - CARTHAGE, MISSOURI
[LUMINAIRE] 1/175W CLEAR ED17 MH LAMP 16x16"DIRECT WALL MNT LUMINAIRE
[MORE] SEMI-SPECULAR REFLECTOR SYSTEMS w/BLACK BLADE BAFFLES
[MORE] .1875"THICK CLEAR TEMPERED GLASS LENS
[LUMCAT] WPSQ-MH-175-MED-120
[LAMPCAT] M57 (M175/U/MED)

The only mandatory keyword here is "IESNA:"

The start of the file you mention looks like this:
ERCO Leuchten GmbH BY: ERCO/LUM650/8701
74216023+Q50MR16/C/CG55°-FNV.IES
-
-
-
-
-
-

Just replace all of this with:
IESNA:


And you should be good to go.
/Sigstan

User avatar
Marcel2586
Posts: 413
Joined: Sat Mar 05, 2016 7:42 am

Re: Reality and IES

Postby Marcel2586 » Sat Mar 25, 2017 4:08 am

Thank you Sigstan. This solved the problem and it is working like a charm.
i am busy with a shop window and i wanted some light cones on the wall and this is just working great and puts in more realism into the scene.
reality_scene.png
this would be funny if it weren't happening to me :shock:

User avatar
sigstan
Posts: 416
Joined: Sat Jan 24, 2015 3:59 pm
Location: Denmark

Re: Reality and IES

Postby sigstan » Mon Sep 11, 2017 2:38 pm

Updated expired Dropbox links in tutorial.
/Sigstan


Return to “Tips, techniques, and recipes”

Who is online

Users browsing this forum: No registered users and 1 guest