How Do I Light My Iray Renders? (All Turning Out Dark)

SubGeniusZero

Hi there. I'm a longtime DAZ Studio user (currently using version 4.10 on a Mac Pro, with High Sierria, quad core 3.7 GHz Xeon, dual 2GB FirePro cards, 32GB RAM), but I'm completely new to using IRay for doing my renders (up 'til now, I've only used 3Delight). And on my computer, Iray only uses the CPU, of course, since I only have an AMD graphics card. But, anyway, the quality is lightyears  beyond 3Delight, and I want to learn more about how to properly light and render with Iray. So far, my first scene is turning out rather dark and dismal, even though I think I've lit it pretty thoroughly. I've got three ambient lights, positioned in a triangle around the figure, (two in front on either side, one in the back), and three spotlights above the figure, likewise positioned. Plus, I've got UberEnvironment+ 2 thrown in there, set to to Bouce Light (GI). The ambient lights are set to 2500 lumens. But what I get is what you see in the screenshots. It's like Iray is ignoring the lights. What am I doing wrong? Thaks for any help in advance!

—Andy H.

Fishtales

The 3Delight lights don't work in Iray. The Dome gives the ambient light and all the other lights you add must have Photometrics turned on before they will be used.

SubGeniusZero

Okay, I turned on Photometrics on all three spotlights AND ambient lights, converted all my Surfaces to Daz Uber Iray shaders, and selected "Dome And Scene" in the Iray Environment section. Still turning out dark. What else should I do?

Fishtales

 UberEnvironment+ 2 doesn't work in Iray so it can be deleted from the scene. To get the scene lighter you can try setting the Tone Mapping settings to gather more light. The settings work the same as a camera if you are familiar with those.

BeeMKay

You could use a combination of Sun&Sky setting (you have to experiment with the time of the day), and the headlamp that comes with the camera. The headlamp is usually a good light source when you tune it down from the bright-light 1.0.

Here's some example renders and settings:

Using the sun&sky:

Using default dome&scene:

As you can see, the different light sources have a different influence, i.e. when it comes to reflection colours on the bling parts of the costume.

Also, here is a thread that covers a few basic concepts about Iray lights, which might be useful. The particular thread is about lighting rooms, but it might still help you. https://www.daz3d.com/forums/discussion/110771/natural-iray-lighning-for-rooms/p1

SubGeniusZero

Thanks for the tips. I figured out that by playing with the "Exposure" setting in the Environment tab, and my playing with the Luminence values of the lights, I could make it light the scene correctly. However, your tips about Sun & Sky are very helpful! Thanks! Now I have a different question: I have some Shaders that won't work in Iray, such as Dimension Theory's "Strange Substances." So, I applied one of the Shaders to an object, then selected the surface in the Surfaces tab using the Surface TooL, then went to Shaders > Iray in the Content Browser, then selected Daz Uber, then double-clicked on Iray Uber to convert the Shader over to being an Iray Uber Shader instead of a regular Daz Shader. The conversion went okay, but the Shader sitill won't render properly. So I went in and looked at its properties. Sure enough, it's set to be an Emissive texture just as it should be (these Shaders do emit light, at least in 3Delight), and the .hdr file was loaded in correctly into the Emissive slot (which was set at a neutral white color itself), but the Temperature was set at zero. So I turned up the temperature to 6500K. Tried to render. It STILL won't emit any light, stll shows up as just black. So I tried fiddling with the Luminence control; turned it up to ten. Still no go on the texture showing up. What am I doing wrong, here?

—Andy H.

 

Fishtales

The Luminance at 10.00 is very low and try setting the Luminance Settings to cd/cm^2 instead of the default cd/m^2

SubGeniusZero

Okay, that helped, thanks. I still can't get the Strange Substances to work — I'm still working on that, and will report back what happens — and at the moment I'm playing with the render settings, trying to get my Iray renders to not turn out so grainy. Currently, I've got the Max Samples set to 10,000, the Max Time set to 9,000, the Convergence set to 99%, and the Render Quality still set at 1%, because anything above that value I've found balloons my render times to near infinity. Is there anything else I should do to try and reduce the grain in the renders? 

BeeMKay

I have Strange Substances. Which one of them is giving you trouble?

By the way, if you also add the hdr to the Base Colour slot, the colouring will come out better in some cases.

SubGeniusZero

Thanks BeeMKay. The one that's giving me trouble is one of the four silvery purply swooshy ones that looks like melted chrome. (Gee, does that help narrow it down? I hope so.) I can't get it to show up at all. I'll try adding the hdr to the base color and see if that helps, though. Thanks!

BeeMKay

I'll give it a look tonight, but it id possible that they are "mathematical" shader settings that do not translate to Iray at all.

BeeMKay

I've checked out the lights and it's like I feared. They are special custom shaders and have some settings that won't easily rtansfer to Iray. I don't know enough about Iray shaders to copy the effect, and my test have not had much success.

 

SubGeniusZero

Oh well. Thanks for checking that out anyway Bee. I appreciate it. I guess I'll just have to find a way of getting that same effect in some other manner. :-/ Ah well . . . the show goes on, I guess . . .

kalina.pepa_29135cfc8e

Fishtales said:

The 3Delight lights don't work in Iray. The Dome gives the ambient light and all the other lights you add must have Photometrics turned on before they will be used.

and what should i do, if Photometrics is ON, and still Dark render? 2 spot lights, pointing directly on figure head, and render is just dark.. black.. like no lights there.. using Sun and Sky helps, but i need to lit up the ehad..

My 3D Spin

Try to up the ISO in Render settings Tone mapping...

Axelx10

Up the ISO?

Tone Maping?

Max Samples?

How about something simple like couple of setting dials?

Lighting on/off

Brightness: Increase/Decrease

Axelx10

There is a great product in DAZ called Great Lights. It answered all my problems. Iray lighting you can adjust and actually see it adjusting while you adjust it. Brightness, angles, all that. No more messing around in Render settings. There are some things in here for that too.

https://www.daz3d.com/great-lights-and-props-for-iray

This image I stopped after 20 minutes. Still renders slow, but thats another issue. You can see though that the lights are on in the environment and I added one spotlight. You might have to turn down the Glossy Layered Wieght in some background props but not much. The thing is here....Lighting you can adjust and control...that actually adjust.