problem with ies and sun/skylight

[vikoum]

hello to everyone.

 

it my first post here and since now i found very interesting the whole site.

I hope someome can give me a hand with a problem i deal with in max. I use max 2010with vray 2.

I have to make an exterior night scene of a building with some lights on its forefront.

I have thε lights i need from the manufacturer so the max file of it.

When i insert tha max file of the light and the ies, i state again the ies curve from the web photometric file but when i render only with vray sun (small intensity) my light does not lit. It seems like it is enabled but it is not.

What i propably do wrong? I an not sure that i use correctly the sun maybe.

 

Can anyone help me???

Please.....

[Jonathan Sanchez]

Hmmm.. you've tried raising the light's strength?

[Crazy Homeless Guy]

You are using the sun /skylight for a night scene. These are good for day scenes, but not dusk or night. Because you are using the sun and sky system the exposure on your camera is jacked.

[Dave Buckley]

if you are using the daylight system for night, the sun will be below ground, so you may aswell turn it off (unless you were hoping it could be used as the moon by lowering the intensity - which would mean you still have it at a mid-afternoon setting).

 

If it is below ground and therefore turned off, then you are left with just the sky, so why use a daylight system anyway? use a dome light to simulate the sky.

 

but travis is correct, it really screws up the exposure in both vray and mental ray, max is still reading it as a mid-afternoon setup - not night. Mid afternoon and night would require completely different exposures.

 

I remember trying this in mental ray, i ended up with my sun set to about 0.001 and the exposure set to a unitless value

 

rather than think of it as a daylight system - think of it as a sun/sky system as that's what the assembly is made up of, it isn't a sun/sky/moon setup

[vikoum]

i want to thank you all for your replies.

 

sancheuz, i've tried to raise the light's strength but nothing. I could say i've tried almost everything but i have reached a dead end i think.

 

I have seen some renders via net that represents residences late afternoon but some exterior lights are on and they look prety nice.

 

Buckley, your comments are right and i thougth about the sun beign under ground or off. I also used a dome light to simulate the sky, or to lit my scene jyst with an hdri image which worked pretty fine. A very loww intensity ex.0.002 didn't work either.

 

I even tried to set any system i used for daylight, to its minimum value, but still my ies lights didn't show up in my scene.

 

do you suggest i should make some adjustments to my camera?

I don't want to put my scene at night, a late afternoon setup woul be ok. as long my ies lights works. i am still working on it and i do again and again every different setup, in case I missed something.

 

If aynone has used ies lights even at an afternoon scene i would appreciate his help with that.

 

I want to complete this project by using vray, i even did all my materials and the only thing is missing are ies lights. Until now, i used only scanline and i wouldn't like to downgrade this project to scanline again.

[Ismael]

Show a picture of what a render looks like now and provide information as to the camera you are using.

Have you tried any other Vray light or standard spot instead of the ies lamps?

[vikoum]

good morning...

 

i am here again beause i have some news with my problem.

 

i managed to have a vraysun with very low intensity and ies lights.

[ATTACH=CONFIG]41823[/ATTACH][ATTACH=CONFIG]41824[/ATTACH]

BUT, i found something weird about vray ies lights and i am refering to the target of an ies light.

The second think i can't understand is the power that an ies works.

As you insert an ies light you have to state a photometric curve and usually if you take this curve from a manufacturer, then you knos tha tis curve is with a lamp LED 4w that has 150lumens.

In the power box that a vrayies light has what units represents?

 

I have attached 2 jpgs with one render with vray ies lights and another one with some comments/questions i have on it.

 

 

[Ismael]

Your original problem might have been that you must have unchecked, "Use 3ds Max Photometric Scale".

"Use 3ds Max photometric scale - when on (the default), this option aligns the VRayLight, VRaySun, VRaySky and VRayPhysicalCamera to the photometric units used by 3ds Max and its photometric lights. When this is off, these plugins operate in the internal V-Ray photometric space, like in older versions of V-Ray. Keeping this option on ensures that a VRayLight with a given power will match a 3ds Max photometric light with the same power." From the Vray 1.5 online manual.

 

Also, make sure to turn Max Exposure control to None.

 

*** The light units are in lumens and as far as the target is concerned, it has to do with what vieport you were when you dragged it from resource browser. Try with a top and a bottom viewport.

Edited March 14, 2011 by Ismael
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[vikoum]

ismael thanks for your tips but i checked both of what you said and the setups are just how ou said. the 3ds max photometric scale is on by default, i didn't changed it and my exposure is also none.

 

the power of an ies light in measured in lumens, i fnally found it.

Still i can't understand why the target work reverse