Material Series
Version 2.0, Updated Feb 2025 using Octane 2024.1.2 and Cinema 4D 2025.1.2
~2,500 words, average read time: 15 min
About this guide
This guide explains what the Universal Material is, and how to think through building any kind of material in Octane using it. This is meant to complement the updated Channels Deep Dive guide, which gives more information about each channel.
Part I is an introduction to the Universal Material, and how to work with the channel attributes, Part II is a series of ten questions to ask that will guide you through building various types of materials from scratch.
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Part I
Introduction
The Universal Material
Octane has several different types of materials, all of which can be accessed from the Live Viewer window under Materials>Create. There are a lot of them, and most of them are still there for compatibility with scene files built in earlier versions of Octane.
The Universal Material is one of the more recent-ish additions, and it replaces the need for just about every other material type in Octane moving forward. This guide, and most of the others will focus on this material type because it’s extremely versatile - we can make any type of material with it quickly and efficiently.
We can convert most other types of materials (Metallic, Glossy, Specular) to a Universal material by selecting it in the dropdown in the Basic tab of the material (or at the top left of the material properties in the node editor).
Channels
The most important thing to understand about materials in Octane (and most physically-based render systems for that matter) is that they are broken down into a stack of channels. Each channel describes a different property of the material (how reflective it is, how transparent it is, etc.).
Most of the different material types in Octane have a small subset of all the available channels, but the Universal Material has all of them (hence “universal”). This can be a little overwhelming at first, but once we go through this guide and understand which ones we need to use to get the look we want, it starts to make a lot more sense.
Important: turning off (unchecking) a channel in the Basic tab of the material does NOT remove the channel’s contribution, it simply hides the channel from the UI. If metallic was at 1, and we uncheck the Metallic channel in the basic tab, the material will stay at metallic=1 until we turn it back on and change the slider.
Channel Contribution
All channels have one or more possible inputs that describe how much that particular channel contributes to the overall material. The UI across all channels usually boils down to three types of controls, and there’s a strict hierarchy of what overrides what when all three are in the same channel.
At the top of the hierarchy is the Texture Input. If an external texture (image or procedural pattern or something like that) is hooked up to a channel that supports it, that will override everything else.
If the Texture Input section has a Mix slider, then we can do a simple blend (think Opacity slider) between the texture and the color or float under it. For more complex mixing and layering, check out this guide.
Below the Texture in the hierarchy is the Color Picker. The picker is overridden by the texture, but it overrides the Float value.
The Color Picker assigns an RGB color to the channel’s contribution to the material. What the picker looks like depends on whether we have it set to Cinema 4D Native or Octane Native . This option is found in the Octane Settings, in the Settings tab, in the Other subtab.
Bottom of the list is the Float value, and this is where things can be confusing.
If there’s no texture input, and the color picker is set to 0,0,0 (or #000000, or the equivalent of pure black in whatever mode we’re in), then the Float slider acts as a linear 0-1 slider with 0 being no contribution, and 1 being full contribution. This isn’t super useful in the Diffuse/Albedo channel because we usually want nonlinear visual color values, but it’s good in the Specular channel if we want to make the material more or less glossy.
Important: If the Color Picker is set to ANYTHING other than black, and/or there’s a texture input, the float slider will do absolutely nothing. There’s no blending between the Color Picker and the Float value - it’s an either/or situation.
Turning off the Channel’s Contribution
If the color picker is set to 0,0,0, the float is set to 0, and there’s no texture in the texture input, the channel has no contribution at all to the overall material. This is an important concept, because most of the time we are only going to want a few channels to have control over the properties of the material, and the rest need effectively be turned off to do this. Again, unchecking the channel in the basic tab doesn’t turn it off, so this is the only way to ensure a channel won’t muddy up the material.
Part II
Thinking Through Creating a Material
Let’s take a look at ten questions that will determine how to build nearly any material. This is just an overview that will help us think about which channels to use. For more information on what each of the channels actually do, check out the Universal Material Channel Deep Dive guide. For examples of these to dissect and explore, look at the Universal Material Starter Set.
Step 1: Is the Material Metallic?
This is the very first decision we should make. The Metallic channel overrides nearly everything else, including Specular (glossy) and Transmission (glass). There may be a call for a material that’s semi-metallic, but more often than not it just makes the surface murky and difficult to work with, so usually we want this slider either at 0 (not metallic) or 1 (metallic).
If we’ve decided that we want a metal, we’ll need to color it and control the reflective properties. This is determined by the IOR type. Artistic is the default, and easiest to use - the Albedo color controls the metal color. The other two types (IOR+color / RGB IOR) are great when we have real-world values for a particular metal, but we can often get the same look or close enough with Artistic as we can see in the illustration above. The Channels Deep Dive guide explains this in detail.
The Roughness, Anisotropy and either Albedo or IOR channels (depending on the IOR type) are used to adjust the look of a metallic material.
The BRDF model makes a large difference when roughness and/or anisotropy is involved. GGX (Energy Preserving) usually produces the best results in this case.
Step 2: Is the Material Opaque, but Not Metallic?
Matte and glossy materials include wood, plaster, opaque plastic, fabric, etc.
For these types of materials, we need to make sure the Metallic Channel is set to have no contribution (metallic=0). Then adjust the Albedo and Specular channels to determine the color, pattern, and how glossy the material is.
If we’re making a fully matte material, we need to set the Specular to 0, 0, 0, float 0.
Important: The float of 0 is key - The specular channel defaults to 1, so if we’re not used to looking at the float it, we may end up changing the color to black and still wonder why the material is glossy.
If we’re making a glossy or semigloss material, the IOR (Dielectric), Roughness and Anisotropy channels will control the look of the reflection. The Specular channel can either be white to just have a clear gloss, or be tinted by adjusting the color. A texture can also be fed into specular to break up the glossy look (like for wear and tear or patterning).
Important: The color impacts how glossy the material is. Colors with a high Value (V in HSV) are shinier than ones with a lower V, and certain colors like yellow appear shinier than others like indigo.
Step 3: Is the Material Emissive?
Does it generate light? If so, we’ll want to start by bringing the Albedo, Metallic, and Specular channels to 0,0,0, and make sure the floats are also at 0. Those channels can muck up emissive materials, and most of the time we want them to have no contribution.
After that, we need to decide how we want to control the color and other properties of the light. We do this by adding either a Blackbody Emission or Texture Emission node into this channel and adjust the settings in the Emission channel.
Emissive materials in Octane usually look pretty nice with Bloom/Glare, so we’ll want to be sure to set that up in the Imager.
If we want the material to look like a frosted light bulb or glowing plastic, we can add a Coating (Step 9) or embed the object with the emissive material in another piece of geometry with a glass texture.
Important: Emission is one of the main causes of fireflies, artifacts, and overall stress and rage in 3D. It’d be worth reviewing the lighting and emission guide to understand how that all works.
Step 4: Is the Material Translucent?
Will the material be translucent like plastic or wax or water or something like that?
First, we need to set the Albedo and Metallic channels to 0,0,0, float 0 so they don’t contribute and muddy up the appearance.
The Transmission channel is what controls the refraction of the material, so we need to give it a color or a float value - it’s always best to start with white or float 1. The darker the Value (V in HSV) of the color, the less translucent it’ll be.
Important: The IOR channel controls the IOR of both the Specular AND Transmission channels. In the example above, we’re looking for a glossy polished glass, but when we crank the IOR to 3, it gives unrealistic refraction. What we can do instead is set the IOR back to ~1.5 (real glass), make the Specular 0, and then apply a high gloss in the Coating channel (IOR 4) so it’s super shiny, but still refracts properly.
If we’re after a clear material like glass or water, we want to set the Transmission type to Specular in the Transmission channel.
If it’s more like a semi-translucent plastic or jade or wax, we can set the Transmission type to Diffuse and might be able to get away without SSS.
For a soap bubble or blown glass, we want Thin Wall. For leaves, lampshades, and the like, Thin Wall (Diffuse). is the right choice.
If we want imperfect refraction (that rainbowy look), the Dispersion channel is where we’d go - this is hard on the GPU, so we need to be careful.
Step 5: Does it Need a Medium?
The Medium Channel works in conjunction with the Transmission channel to create Subsurface Scattering and Absorption effects. These are good for plastics, liquids, skin, and anything else that’s semi translucent. Scattering in particular really beats on the GPU, so make sure we want to be absolutely sure that we need these effects and our scene will show them off. More on that in the Channels Deep Dive and Volumetrics Overview guides.
Step 6: Are Textures Needed?
Now that the type of material is set, we should decide whether it has a completely smooth, uniform surface, or if one or several of the channels need to be broken up to add detail and variation across the surface. Textures can either be bitmap images loaded from disk, or procedurally generated via Octane’s nodes (noise, etc.).
Important: Remember to use ImageTexture nodes for bitmap images.
Step 7: Does The Surface Have Depth?
The Bump, Normal, and Displacement channels all determine what the surface of the object looks like. These seem straightforward, but there’s a lot that goes into them. Check out the bump and normal guide & displacement guide series for more.
Step 8: Are Any Special Effects Needed?
The Thin Film, Dispersion, Opacity & Round Edges channels produce specific effects on the material or geometry.
Thin Film is responsible for iridescence, and works best with metallic or very glossy non-metals.
Dispersion gives a rainbow effect caused by imperfect refraction.
Opacity is for fade in/out effects like a transporter, holes in a thin surface like paper, or intangible objects like a hologram. It is NOT for glass - that’s what the Transmission channel is for.
Rounded Edges is a render-time effect that rounds sharp edges and is good for adding just a bit of realism to overly sharp geometry. This channel is hidden by default and needs to be enabled in the basic channel if we want to use it.
Step 9: Does the Material Need a Top Coat?
The Sheen and Coating channels go over the top of everything else to give the material an extra glossy look or a fresnel-like sheen.
The Coating channel puts a thin gloss layer over the top of the material. The overall Roughness and IOR channels affect both specular and transmission, but if we use the Coating channel - which has its own roughness and IOR - we can separate that out so we’re only roughening and changing the glossiness of the reflections without messing with the transmission properties as well (as seen above).
Sheen is good for fabrics and other materials where the reflection falls off toward the areas of the object that we’re seeing flat-on. Sheen can take a texture input into its bump parameter to break the effect up.
Step 10: Does the Material Need Layers?
Most material types support Material Layers, which can create some very complex multi-surface materials. The mixing and layering deep dive guide covers this in exhaustive detail.
Important: As of this writing, the material layer pin is hidden by default - we can enable it in the Basic tab of the material properties.
Wrap Up
This should get you started building your own materials. It takes practice and learning about all the various things that make up a material, but with a good foundation and understanding, it becomes pretty quick and painless.
If you know we’re looking for a physically correct material, you can consult a site like pixel and poly, refractiveindex.info or matmake.com to find the right values.