IRAY=DARK
Angelman
Posts: 42
in The Commons
Ok so I have been using the Iray for rendering and when I do, the pic stills comes out dark, even when using distant light and spotlights on the model. Any ideas on settings that I can look at and change for better lighting when rendering in IRAY? Frustrated!

Comments
Change the tone mapping exposure on the render settings tab. I frequently end up doing that to get a ligher picture.
First thing is simply to increase those lights. Distant light is a little weird, and spotlight can need absurd-sounding luminance levels to be 'right.'
Second thing is, if you have Photoshop or something else that can handle 32 bit images, turn on Iray Canvasses, add a 'Beauty' canvas (IE: a regular render at 32 bits), and tone map in Photoshop (or whatever).
Are you rendering indoor or outdoor scenes? Outdoor works much better because the dome gives light. If outdoors, you can try increasing Environment Map setting under the Environment tab to 6 or 8.
For indoors, try increasing Film-ISO under Tone Mapping tab. If it is at 100, jump it up to 400 or 800. If too bright then, you can reduce the value. If still too dark, increase it further. Iray renders faster with more light, so Will's comment to increase the light intensity or lumens is important to try too.
Will? how do you increase the intenesity of the lightsm when using the distant and spotlight. What does the Linear light do in a pic?
(fixed unused quote - mod)Make sure you have the head lamp shut off in your camera settings. That will cause black renders.
How much of the lighting are you changing from the default settings? In this case "default" means:
So, if your intended lighting isn't "bright sunny day", you need to look at those defaults and start adjusting.
Actually, the first thing to do is make sure you don't have a skydome from a set blocking the light
You didn't say what you are rendering, and I've read far too many threads that ended up being the skydome from a product was interfering with the setup. What are you using, and does it have a skydome loaded?
The only thing I wil add is that you really should try to avoid the headlamp. Use it as a very last resort or to produce a very specific look. Personally, I really wish it didn't exist at all but it seems Daz added it for newbies to avoid the black screen when first press the render button with no idea of what they are doing. Fine. But sometimes users fail to grow beyond this beginner's tool even after months and years. Using it all the time has visible signatures. The headlamp tends to flatten the results of a final render by hiding the shadows cast by the headlamp behind the figure instead of casting those shadows into areas where they can be visible to the camera. Shadows are what add 3d depth to a scene in most cases, so a scene lit primarily by the headlamp will have hidden shadows and will thus appear flatter. One must always be mindful of how they are managing shadows, don't take them for granted. Once you get the other types of lights going (distant, environment, etc), you won't need the headlamp at all 99% of the time. Best of luck.
Oh, and for a quickie help tutorial, check out the lighting one in my signature. It's SIMPLE but addresses the Render Settings and what Tone Mapping sliders do and why they move together (and how to balance it, which one to move first IMO for easy workflow.) THE LINK IS CORRECT BUT NOT WORKING, don't know why. Scroll down a few posts and it will be the tutorial.
One other option, that I have used with good results, is to lower the 'Shutter Speed' setting (it defaults to 1/128 sec), and/or to raise the 'Film ISO' parameter.
I generally reduce the shutter speed to about 1/60 sec, and crank up the ISO to about 400.
The ISO harkens back to the days of film, so you need to pull your mind-set back to when there was actual film in the camera. (The higher the ISO value meant that it was a relatively fast film, which meant that it did not take a lot of light to get the film's emulsion to respond; the shutter speed refers to the amount of time that the film was exposed to the light that the lenses focused onto the film's emulsion.)
Think old-school photography (F-stops, shutter speed, and such).
I keep hearing about this head lamp..where is it? grr
Select a camera, then either in Parameters or Camera tabs, there will be a Headlamp control.
Any 20 people will give 20 different answers, lol
All the advice already given is good. Also, the spotlight, distant light and point lights load up a default setting that barely make any impact, and in some cases, none. Try increasing the Luminous Fluix (Lumen) by several thousand. I think they load at 1500, and I usually put them at 50,000 to get a starting point.
And in Render settings under General, turn it to Never.
http://sickleyield.deviantart.com/journal/Tutorial-Lighting-and-Tone-Mapping-In-Iray-531864617
Its seems the fall off on photometric lights in Iray is huge. For example of i use a spot light on my subject and set the lumen level to 50,000 in order for it to give good light on the subject it needs to be like 2 feet away from my model. As you move the light back the lumen levels increase dramatically.
Daniel
Sounds similar to the effects described by the inverse square law in photograpy. Similar.
Dana
Um...yes, the fall off is 'quadratic' or inverse square. That's what real life fall off is...