If you’ve recently switched to Octane Render from Iray, you’re probably scratching your head on how to do lighting. Setting up lights with Octane is a night and day difference when compared to Iray. There are no spotlights or camera headlamp to get things going. We will almost entirely rely on simple mesh lights. We’ll put aside a full lighting tutorial for another day, for now we’ll focus on getting those gorgeous eye reflections with Octane. Without those eye reflections, our characters look dead inside, just like me. We want to avoid that level of realism.
I’ve recently moved to a new system and forgot about this additional step required until I realized I couldn’t create eye reflections. In the Preferences tab, find “Surfaces Material Filter”. It may have some items already listed in there like “Cornea”. Whatever names are listed here will be filtered out and ignored from Octane materials. By default, Cornea is included which makes eye reflections impossible until you’ve removed it from the filter list.
OPTIONAL: Create a plane and place it centered on a camera. Make the camera the parent and save this as a prop for future use. You will then be able position your light by assuming the camera view. This will save you countless hours down the road.
For this example, we’re going to use Hikari as our model. Let us pretend that we have low standards and consider this to be good lighting. I quickly put together three mesh lights to illuminate her.
Okay, we’re happy with the general lighting. Her hair is highlighted, we have some shadows on the face and she’s completely oblivious to the eternal darkness behind her. Hey, where are the light reflections? Other than a small blip on her right eye, there’s nothing there.
Remember, Octane Render doesn’t have any spotlights or camera headlamps so we’ll have to add a mesh light.
Great news, we see light reflections in both eyes. Bad news, she literally looks like a deer in headlights just moments before impact. Don’t worry, with Octane Render we can have our cake and eat it too. Head into the Materials section in Octane Render and select your mesh light. We will be looking at Opacity, Power, Temperature and the Visible on diffuse button.
I always start off by setting my mesh lights opacity to 0. I don’t want the floating light pane to be visible in the scene. Only lights that are part of the environment such as ceiling lights, lamps, etc, should be visible. Let’s move on to setting the Visible on diffuse to OFF. Setting diffuse to off essentially removes visible light from the scene. All that’s left is specular light which is the light reflection on surfaces. This is exactly what we’re looking for.
Also, notice the extra shine on Hikari’s skin? Setting up lights with diffuse off is an excellent way of creating shine or glow.
Great, this is what we wanted. Hikari has some new eye reflections without extra visible light entering the scene. It still looks a bit odd though, as if a light source is directly in front of her face. Let’s change that. First, I will show you a really cool and obvious way of working with lights that I’m embarrassed took so long to discover. Thank you for teaching me, PhillyGames, you’re the real MVP.
The biggest draw to switching from Iray into Octane Render is the near-instant live viewport and the increased render speed. Well here’s one more thing that will ensure you never switchback. Get ready to have your mind blown.
Set up your camera however you like. Once you’re happy, head to the top left corner of your Viewport and select the button that looks like a grid. When hovered it says “Limits the rendering to the selected region”. This is basically the Spot Render Tool we used with Iray.
We want to render only the area around Hikari’s eyes as we are focusing on getting eye reflections. Draw your square, smash that lock-button in the bottom right corner and set it to Current Camera. Now we can move around in Daz and Octane will continue rendering from the view of the camera we locked it in. This means we can start moving around our mesh light and instantly see how it’s reflected in the eyes. Bonus points if you have a second monitor where you can throw the viewport on.
I didn’t like that our light was a square plane so I widened it. The dead center placement made it look like she was about to shoot laser beams out of her eyes. I raised the mesh light up until I was happy with what I saw in the Octane Render Viewport.
This already looks so much better than what we previously had, but the reflection was a bit too strong for my taste. After lowering the power of the mesh light from 100 to 5 and adding a second light, this is the final result.