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Tutorial: Lighting in OctaneRender

By Piotr Rusnarczyk

Web: http://sexy-polygons.com/

Piotr Rusnarczyk, Senior Character Artist at Flying Wild Hog, breaks down the best features of OctaneRender to demonstrate how he created his spectacular work, “H.A.S.H.”…

OctaneRender is a really powerful tool for artists who value photorealistic effects and fast rendering. Octane mainly draws energy from the graphics card GPU memory, usefully taking load off your CPU. At a few points in the tutorial I will try to approximate the technique of modeling lighting using HDRI maps, and I’ll share the render settings for my model “H.A.S.H.”

To illustrate, I used one of my head models that I sculpted in ZBrush. I exported the individual parts of the mesh using OBJ format. All textures were baked in ZBrush and exported in PSD format, mainly texture diffuse and displacement map.

Step 1: OctaneRender interface

Version three of OctaneRender has been upgraded with really useful new tools for customizing the interface. Octane windows are grouped in four basic parts: 1.) Render window 2.) Scene widow 3.) Node inspector, where we can change a node’s parameters 4.) Scene outliner, where we can find and use materials from local libraries or use LiveDB.

We can undock and customize the windows according to our own preferences. I mainly use a layout with the Scene window occupying the largest area, because I use it most frequently. At the bottom of the rendering window is the render view toolbar. My first step before I start setting the scene is to adjust the render priority setting; I usually set it to “low.” Although this lengthens rendering time, it reduces load on the graphics card making it easier to work with other applications (for reference I have a Geforce GTX Titan X with 12 GB of memory in my workstation.)

Step 2: Import mesh to OctaneRender

We start by importing a mesh into our scene; right-click on the Scene window and select “Import mesh.” If we load more than two meshes into the scene we have to use the Geometry group node to connect them together.

When we have loaded all the elements of our scene we can mark the node with the object, and in the options tab click the icon with the key picture (Edit setting geometry files.) The main part of the head is a subdivision mesh, so I’ve set the subdivision level to “1” and left the rest of the settings unchanged. In the options window you can also set parameters such as smoothing angle, the type of subdivision and more.

If you’ve made changes on a model you can use the Reload icon, beside the Setting icon and Import mesh – In the top left corner of the window. For items in the scene to be visible, we have to connect them to the node (the render target.)

Step 3: Camera setup

Using nodes in the Octane is very convenient; I have used them to create several camera settings: Front view, ¾ view and Profile view. Navigation of the camera in Octane takes place in the render window. This makes it more intuitive than in standard 3D applications. Navigating the camera is possible using keyboard shortcuts and the mouse. We can also define our own shortcuts, which is very handy when transferring navigation preferences from another application.

Step 4: Materials setup

I used two types of material for this scene. I used a Glossy material type with base color and displacement textures for the head elements of the mesh. For the eyes I used simple glass material from LiveDB. Octane has quite a good selection of ready to us base materials, many of which are really useful; glass or metal for example. Organic models has some nice materials for skin, of course we can improve them in our own way. For the lighting on the head I used a Diffuse material with emission on “20k” power; this produced a light source similar to a fluorescent light bulb.

Octane has four types of material:

Diffuse – Used for rough, non-reflecting materials, as well as light emitting meshes.
Glossy – Used for shiny materials such as plastics or metals.
Specular – Used for transparent materials such as glass and water.
Mix – Used to mix any two material types.
Portal – Used to designate openings in scenes to allow the render kernel to sample light from those areas better.

Step 5: Basic lighting setup

One great advantage of Octane is the ability to very quickly light the scene to see how it will affect your work. I always use the Daylight environment at the beginning – In the Sun direction panel you can adjust the daylight using the world map. It allows you to specify the time and season of the year depending on the light you need. One very interesting option is “sky turbidity.” It allows you to slightly soften the edges of the shadows and cause the light to be more diffuse and soft. The render target node has two slots to which you can connect specific lighting and environment maps. For my model I used white color images like a background.

Step 6: Lighting using HDRI maps

In my opinion, lighting a scene using HDRI maps is the power of this program. Even from my first steps in Octane, I knew that I was going to have fun testing the available maps and creating my own. In fact; every picture with appropriate parameters can be experimented with to illuminate a scene. To make our effects more realistic it’s best to use high-dynamic-range maps. We can download maps from the web, where there is a rich library of free HDRI maps, or we can create our own using programs like HDR Shop or HDR Light Studio.

For the lighting in my scene I used a free HDRI map from hdrmaps.com. I experimented with textures setup and in the end I chose the following parameters: Power 1.00, Gamma 0.808, UV Transform R.Z 70, SX and SY 10.835, and Power 5.614. I recommend saving different parameters in the nodes, and put them on local binary – they may be useful in the future.

 

Step 7: Additional lighting

For additional lighting I used a mesh of a specific shape, I wanted the curious shape to be reflected in eyes of my model. I set material with Emission value of 100.0 to resemble the effects a fluorescent lamp. I placed the light in the frame to complement the composition and the picture took on additional space. Sadly, soft light tends to flatten a picture. I used depth of field in the camera with aperture parameters 100.

Step 8: Images setup

Octane has some very useful tools that we can apply during rendering that will affect the appearance of the final image. We can change the color temperature of the image (White point,) add a vignette to the image, or alter image saturation. I would recommend testing the response filter set for the desired effect. For H.A.S.H I used the following settings; Response: Agfacolor HDC 100 plusCD, White point: Red 0.977226, Green 1.0, and Blue 0.991426.

Step 9: Rendering setup

I usually use two ways to save renderings in Octane. First, when I need to save a renderer view I use the button at the bottom of the window to save the current render to disk. If I’m sure of the final effect of my work I use Batch rendering. I just choose the location where I want to save the picture, click “Start” and go for long-awaited and well-deserved coffee.

Tips

To center or find an object in the scene use the icon preset the camera to a pre-defined viewport

When setting up quality rendering, sometimes it makes no sense to set Max. samples to more than the image resolution. For example, if your images resolution is 2048×1024 set Max. samples 2048.

When you start building a scene, deselect geometry nodes and material nodes, because every time you click on the node the camera will change. This option is very annoying and it interferes with the flow of work.

You can use Octane to create your own simple HDRI map. Build a scene with objects with attached emissive material with a panoramic camera.

Ashif Ali
Ashif Ali
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