IES lights (in Vray)

[only3d]

hi evryone

 

1st of all id like 2 assure u all that i did my best gathering information before i bring up the subject (again) but still there r some loop holes that i dont understand, besides i think its a great oppurtunity 2 make a concetrated thread about the subject (if there is 1 then feel free 2 link it here)

so-

1. how important r the units? is it better 2 use cm or m?

 

2. and lighting units- is there a difference between cd lm or lx? (i know wat they mean but is 1 better than the other?)

 

3. i see in some tuts' that people change the intensity of the light. isnt that wrong? since the ies info is supposed 2 b accurate and 'reallike' isnt it?

 

4. y some ies lights come out great and some r splotchy?(vray settings?)

 

5. can i somehow imply ies info 2 an object? (instead of just making it self-illuminating) if so then how?

 

6. if not then is it possible 2 find lamps w ies light built-in?(kinda like archicad)

 

7. any link or site for ies lights or good lamp models (especially models)

 

Tnk u all in advance. i hope this thread will b good and useful 2 us all

(especially us newbies (-: )

[Ricardo Eloy]

Let's see if I can help:

1. how important r the units? is it better 2 use cm or m?

They're probably the most important thing. Lighting units take meters in consideration, so be sure your System Units settings are correct (they tell Max what size the world is, if you set it wrong, then your lights will come up totally messed up)

 

2. and lighting units- is there a difference between cd lm or lx? (i know wat they mean but is 1 better than the other?)

Units are units. Period. There's no better unit, since you can always find a relation between them. Personally, we work here with "Lx at", since that's the number we get from the light designers.

 

3. i see in some tuts' that people change the intensity of the light. isnt that wrong? since the ies info is supposed 2 b accurate and 'reallike' isnt it?

In fact, that would be not recomendable, since you can assume the info you get with the IES file is accurate for that lamp. But, of course, you can always use only the distribution aspect of the file instead of the distribution AND the intensity.

 

4. y some ies lights come out great and some r splotchy?(vray settings?)

That could happen due to the vray shadow settings. Check the samples.

 

5. can i somehow imply ies info 2 an object? (instead of just making it self-illuminating) if so then how?

Not that I know. Those are light-object dependant, so...

 

6. if not then is it possible 2 find lamps w ies light built-in?(kinda like archicad)

Check out Erco's website. They have some lamps like that there, also dimmered ones.

 

7. any link or site for ies lights or good lamp models (especially models)

www.erco.com

 

Hope it helps.

[Christopher Nichols]

Keep in mind that with IES or "real world" lighting, you need to count on two things. "True" intensity of light, as well as exposure (of your camera). Vray does not really deal with exposure (like lightscape and maxwell), which is a bad and good thing depending on how you look at it. So really when it comes to the intensity of light, what is important is the their intensity relative to each other. They will still decay correctly. But lets say you need more light, and you feel you need to multiply the lighting. Multiply ALL the lights the same amount. I finds that this give the best result. In a sense, the multiplier acts like an exposure... sorta. The other way to deal with it is to use the multiplier inside the color mapping, but this can hold you back some.

[only3d]

Tnx 2 all those who replied (especially u Rick!)

of course any added info will b welcomed

[dom]

for the splotches- check the light model if it has one - ones from erco have max raytrace materials assigned, and I think I read somewhere that vray prefers cm units - theres a tut around on evermotion or somewhere

[wawan1772]

hello

ihave one question about vray ies....how makes VRayIES TARGET in box VRayIES parameter?