IES lights

[F Suarez]

Hi everyone. I’m still using Vray 1.49 (for SkethcUp), and recently I’ve been playing more and more with IES lights, but I’ve come across a problem. Instead of using a generic IES light I tried to use the IES light of a specific lamp, available at the manufacturer’s website (it's under ''Documentation''), but it doesn’t seem to work.

http://lighting.cree.com/products/indoor/lamps/mr16-series

 

When alerted to this, their reply was:

''You will need lighting software to view the information. I use Photometric Toolbox and/ or AGI32.''

 

Maybe VRAY isn't compatible with all IES files?

 

As example, this is the type of IES file that works perfectly on my setup:

--------------------------------------------------

ERCO Leuchten GmbH

3399_0 - IES format

ERCO 89064

ERCO Double Focus Downlight

DL40-QT12-2HA-SI-DOUBLE

1*QT-ax12 100W/12V

light output ratio: 0.5912

ident no. for symmetry: 1

D694

TILT=NONE

1

2200

2.2

19

1

1

2

0

0

0

1

1

100

0

5

10

15

20

25

30

35

40

45

50

55

60

65

70

75

80

85

90

0

681.879276637

557.110079287

490.896871945

628.387368307

682.069349408

430.426577604

286.398935592

254.901162159

76.9183773216

18.9393939394

11.0377973281

.488758553275

.00678831323993

0

0

0

0

0

0

END

--------------------------------------------------

 

I'd appreciate all hints and suggestions.

Thanks for reading.

[John Dollus]

I'd wager it works exactly as intended. The lumen output of the Cree lamp file is 539.4 for the 50 watt version so you will likely have to add a multiplier to vray for it to show up in your render. start with a huge multiplier (1000) and then adjust from there if you are only interested in getting a light scallop pattern on the wall.

[F Suarez]

Thank you very much for your post, John. You are right, the lumen output is indeed the problem, it’s very low. So much that I completely missed it in my tests, my other lights were a lot stronger. Now only using this one.

 

Can you please suggest the best way to add the multiplier?

I tried to change the Power in Vray, but it seems there’s no effect.

I'll attach image.

 

I also tried to change the IES file through Notepad, from

[_ABSOLUTELUMENS] 539.4 to [_ABSOLUTELUMENS] 539000.4

but there’s no change.

 

Thanks again for your help.

Edited December 14, 2015 by fsuarez

[SkylineArch]

It looks like your light is in the ceiling, try to move it down some, and/or, check your render settings, make sure you are setup for interior renderings.

[F Suarez]

Thanks for your post, Mark. I just tried to move the light down a few inches, but no significant change, lumens still very low.

 

Not sure about having everything correctly setup for interior rendering, tho. I learned through tutorials so my knowledge varies from reasonably acceptable to rather incomplete. Where in Vray can I adjust it?

[SkylineArch]

On the top of the vray options dialog there should be a presets drop down, you can start from there.

[John Dollus]

In the VrayIES options, there's a power option right under the color mode option. Change that to increase it.

[F Suarez]

Only today getting back to this, I got some results but i’m still kind of stuck.

I decreased a LOT the shutter speed, to 1.0, and now the lights are visible, but the image has a huge amount of noise.

I’ll attach here the Options Editor settings.

 

Regarding John Dollus suggestion, I tried it, but without success.

As you can see in the first image attached, the power is currently at 9500, but even if I change that value to 950 000, there’s no change in brightness.

[F Suarez]

Any suggestion to decrease all that noise?

It's surely caused by the huge exposure time, but without that the lights are too faint.

 

All suggestions are welcome. Thanks in advance.

[John Dollus]

It's surely caused by the huge exposure time, .

 

nope.

 

In your image, it looks like you are putting the IES source behind some geometry (maybe you are trying to have a lens).

 

IES sources should never be placed withing the actual light location unless you make the fixture geometry not affect the light source (not cast shadows etc)

 

IES is generated by testing the light effect AFTER it leaves the fixture. Remember, these are for engineering analysis purposes; not for making pretty pictures.

[F Suarez]

In your image, it looks like you are putting the IES source behind some geometry

I've been away, but want to thank you for your post. You are totally correct.

To make sure the lights are on the ceiling as in reality I usually place them less than 0.5'' from it, and never had a problem, but this IES was different. As soon as I moved it down a bit, the noise vanished.

 

Thank you very much.