Iray - any useful info or tutorials on lights?

fastbike1

Zilvergrafix said:

Nadino said:

I don't agree with the comment made earlier about Point Lights being useless in Iray. I bought an awesome light set from OOT and it uses Point Lights and they work wonderfully....

Prove it, render it.

let me see why I'm wrong.  

Okay. This is the light set Nadino was talking about:.3 point lights.

Definitely don't get the attitiude. 

fastbike1

Here's a sample with more realistic lighting values. Scene only lighting. 2 1 square meter mesh, each 1200 watts. These are not out of the range of studio lights.

Roughly 1.5 meters from model. Tone mapping F4, 800 ISO 1/125 shutter (realistic camera settings). No post work, 326 iterations NVidia GTX780 

fastbike1 said:

Nadino said:

I don't agree with the comment made earlier about Point Lights being useless in Iray. I bought an awesome light set from OOT and it uses Point Lights and they work wonderfully....

This has been my experience as well.

 I suspect that some of the (early) tutorials recommending very high lumen values didn't fully consider the intent of Iray or look at the developer's blog. As I understand Nvdia's material, Iray is truly designed to mimic real lighting. As such the developer's blog recommends obtaining and using real lighting values. A quick search for photographic studio lighting shows fluorescent lighting units from 200 to 400 watts at 5500K. Various LED units at 3200 to 3600 lux@1meter (~3200 to 3600 lumens) w/ variable color temps of 3200 to 5600K.

These are typical values and not meant to be exhaustive. While spot, point and directional lights can be used, area lights are recommended as more realistic.

I know that I will be experimenting with more real world values and adjusting tone mapping to the kinds of photographic values that I use.

Then again, I could be completely mis-interpreting what I've read (disclaimer).

Zilvergrafix

3 bought point lights for an almost diffuse scene?, you can do better subtle light with simple primitives and emitters, no need to buy a set in rendo for that.

 

 

D.Robinson

Ptrope said:

I'm not looking for an overall lighting as from a dome or any other all-encompassing light source - I'm trying to create a moody light with limited depth, something to pick out a subject. I don't know anything about using HDR images for lighting, but are they useful in place of a point light to highlight a character, which then does not spill over the entire scene?

These are images rendered for the same amount of time - I saw no reason to continue with them when I saw the flood of light in them. One has the point light on at 398% intensity, the other has it off entirely and only the headlamp. I can barely see any difference, even though in the preview I saw the difference - slight but obvious - between having the light on or off.

Point on - 398% intensity

====================

Point off

I know your asking about lights but the problem isnt with the lights its your character. I have this same problem when i use Danika from the daz store without converting her to Iray materials. The thing with Iray is that it does use SSS to gather light information...but the characters that have SSS skin mats are designed to work with 3dl defaults which are too high in Iray. Highlight your character in the scene view...go to the surfaces tab..click on your character in that tab and expand it. Then click on Skin, and expand Surfaces it should have all your skin parts hightlighted scroll down until you see Subsurface strength, it will be at like 75% or higher....lower it to about 2% and your Dark elf should look fine.

Nadino

The product ranges from 2 to 3 Point Lights in the scene. 16 Presets plus a Render Settings Preset.

Fastbike1 has some nicely done examples. Not all the presets completely diffuse the scene either.

 

Besides the point. Point Lights work. That is all I wanted to say - not trying to start a war or have an attitude.

I agree, one can make their own set - but that is much the case with just about most of the products available for sale. We all have our preferences.

A purchased set can really help a user understand the settings better. It was just the right price and very insightful, that's what mattered at the time. :)

Fishtales

Steven-V said:

Fish... how long does a typical render in 3DL or Iray take you? I'm just curious.

I did this scene in Iray and 3Delight and it took the same length of time for both of just over an hour. The only change was the girl on the left. Her skin rendered a nice shade of blue in Iray until I applied the Iray female base shader. 

Left image 3Delight, right one Iray.

Fishtales

This image uses point lights on the candles.

 

I have integrated graphics and Iray and 3Delight renders of the same scene aren't that different time wise. See the post in this thread.

http://www.daz3d.com/forums/discussion/comment/861619/#Comment_861619