The Universal material is designed to integrate with PBRA contemporary shading and rendering process that seeks to simplify shading characteristics while providing a more accurate representation of lighting in the real world. (Physically Based Rendering) workflows, such as Substance Designer. Where the DiffuseAmount of diffusion, or the reflection of light photons at different angles from an uneven or granular surface. Used for dull, non-reflecting materials or mesh emitters., SpecularAmount of specular reflection, or the mirror-like reflection of light photons at the same angle. Used for transparent materials such as glass and water., GlossyThe measure of how well light is reflected from a surface in the specular direction, the amount and way in which the light is spread around the specular direction, and the change in specular reflection as the specular angle changes. Used for shiny materials such as plastics or metals., and Metallic materials isolate parameters to design specific material types, the Universal material can design material characteristics associated with any of the other MaterialThe representation of the surface or volume properties of an object. types (Figure 1).
Figure 1: The Universal material parameters
TransmissionA surface characteristic that determines if light may pass through a surface volume.
Controls how light passes through a transparent surface. It is tied with the Dielectric IOR parameter to control the transparency of a surface. It accepts a color, texture, or value as an input. However, a color input provides the most control. To create colored glass, change the color input to something other than black and set the Albedo to black. Transmission should not be confused with Opacity, which controls the surface visibility. Use Transmission to create a reflective glass surface, and use Opacity to create the look of a hole in the surface.
Transmission Type
Albedo
The material's base color.
Metallic
Determines how metallic a surface looks. A lower value makes the surface look more dielectric, and a higher value makes the surface look more metallic.
Edge Tint
The edge of the metal's color, only used in artistic and IOR+color mode.
Specular
Determines the color of glossy reflections for dielectric materials (when the Metallic parameter is set to 0). The Dielectric IOR parameter needs to be higher than 1.0 for the Specular parameter to contribute to the surface characteristics.
BSDF Model
This attribute provides three options for determining the overall bidirectional scattering distribution function (BSDF). The Octane option produces a brushed metal effect. The Beckmann, GGX, and Ward options produce more polished chrome-like effects.
Roughness
Determines how much the Specular and Transmission characteristics spread across the surface.
Anisotropy
Determines the shape of the specular and transmissive highlights. A value of -1 creates a horizontal shape, and a value of 1 creates a vertical shape.
Rotation
Controls the rotation of the anisotropy shape.
Spread
Determines the tail spread for the specualr BSDF (Bidirectional ScatteringDefines how fast light gets scattered when traveling through the medium. Distribution Function) model of the specular layer.
Index
Refers to the index of refraction for Glossy materials - it determines the strength of reflections on the surface based on the Fresnel law. The Fresnel law describes the physical properties of light as it is reflected off of a surface at grazing angles. If Index is set to a value higher than 1, the reflection is strongest on the part of the surface that turns away from the viewer’s angle (grazing angles), while the reflection appears weaker or less apparent on the parts of the surface that are perpendicular to the viewing angle. The result is a more realistic looking surface. If Index is set to a value lower than 1, then the Fresnel effect is disabled and the reflection color appears as a uniform color across the highlight. The color of the reflective highlight itself is determined by the color connected to the Specular channel.
Dielectric IOR
Controls the Fresnel effect of the Specular reflection or Transmission.
Metallic Reflection Mode
Controls how the reflectivity is calculated for a Metallic material.
Metallic IOR
Complex-valued Index Of Refraction (n-k*i), which controls the Fresnel effect of the specular reflection for Metallic materials. For RGB mode, this serves as the Index Of Refraction for the red light (650nm).
Metallic IOR (Green)
For RGB mode, this is the Index Of Refraction for the green light (550nm).
Metallic IOR (Blue)
For RGB mode, this is the Index Of Refraction for the blue light (450nm).
Coating
Provides a second layer of reflection to the surface.
Coating Roughness
Determines how much the Coating characteristic spreads across the surface.
Coating IOR
Controls the Fresnel effect for the Coating characteristics of the surface.
Film Width
Simulates the look of a thin film of material on the surface. This is useful when you want to create an effect like the rainbow colors that appear on the surface of an oil slick. Larger values increase the strength of the effect.
Film IOR
Controls the thin film's index of refraction. Use this option to adjust the colors visible in the film.
Sheen
Provides a second layer of glossiness to the surface.
Sheen Roughness
Determines how much the Sheen characteristic spreads across the surface.
Sheen Bump
The sheen layer's Bump map. If you don't specify a Bump map, the sheen layer uses the default shading normal. Otherwise, it applies the bump-mapped surface to the sheen layer.
Sheen Normal
The sheen layer's Normal map. If you don't specify a Normal map, the sheen layer uses the default shading normal. Otherwise, it applies the normal-mapped surface to the sheen layer.
Dispersion Coefficient
Increasing the Dispersion value increases the amount of coloration and dispersion in the object’s transmission and in caustics.
Medium
OctaneRender® for Houdini® has three types of mediums - AbsorptionDefines how fast light is absorbed while passing through a medium., Scattering, and Volume - which can be used to create translucent surfaces. To use these options, connect the Medium input of an Octane material to either the Absorption or Scattering medium nodes.
Absorption absorbs light while passing through a surface. The color resulting from this absorption depends on the distance light travels through the material.
Scattering is similar to Absorption, but with an additional option to simulate subsurface scattering. Subsurface scattering is the phenomena that gives human skin, and similar organic surfaces, their characteristic glow under certain lighting conditions. It is a major component in creating the look of realistic skin.
Volume creates the effect of volumetric surfaces when applied to VDBDreamworks’ open-source C++ library housing the data structures and tools implementation for storing and manipulating volume data, like smoke and other amorphous materials. The purpose of OpenVDB is mostly to have an efficient way to store volumetric data in memory and on disk. It has evolved into a more general toolkit that also lets you accomplish other things, such as fracturing volumes, converting meshes to volumes and vice versa. However, it does not include a computational fluid dynamics solver, and therefore it cannot procedurally generate smoke or fire. OpenVDB is fully integrated as a library in OctaneRender. For more information about OpenVDB, please see http://www.openvdb.org/. files imported into Houdini using OpenVDBDreamworks’ open-source C++ library housing the data structures and tools implementation for storing and manipulating volume data, like smoke and other amorphous materials. The purpose of OpenVDB is mostly to have an efficient way to store volumetric data in memory and on disk. It has evolved into a more general toolkit that also lets you accomplish other things, such as fracturing volumes, converting meshes to volumes and vice versa. However, it does not include a computational fluid dynamics solver, and therefore it cannot procedurally generate smoke or fire. OpenVDB is fully integrated as a library in OctaneRender. For more information about OpenVDB, check at http://www.openvdb.org/..
Opacity
Determines what parts of the surface are visible in the render. Dark values indicate transparent areas, and light values determine opaque areas. Values in-between light and dark create the look of semi-transparent areas. You can lower the Opacity value to fade the overall visibility of an object, or use a Texture map to vary the opacity across the surface. For example, if you wanted to make a simple polygon plane look like a leaf, you would connect a black-and-white image of the leaf’s silhouette to the Opacity channel of the Diffuse shader.
Fake Shadows
Activates the architectural glass option for all Meshes sharing that material. When enabled, the Specular material exhibits the characteristics of architectural glass, with its transparent feature allowing light to illuminate enclosed spaces or frame an exterior view.
Affect Alpha
This option lets refraction affect the alpha channel. This parameter has an effect if the Alpha ChannelA greyscale image used to determine which areas of a texture map are opaque and which areas are transparent. is enabled in the Render settings’ Kernel parameters.
Bump
Creates fine details on the material’s surface using a Procedural or Image texture. When you connect a grayscale texture to this parameter, light areas of the texture give the appearance of protruding bumps, and dark areas create the appearance of indentation. You can adjust the strength of the Bump map by setting the Power or GammaThe function or attribute used to code or decode luminance for common displays. The computer graphics industry has set a standard gamma setting of 2.2 making it the most common default for 3D modelling and rendering applications. values on the Image texture node. These attributes are covered in more detail under the Texture Overview category.
Normal
The Normal parameter also creates the look of fine detail on the surface. A Normal map is a special type of Image texture that uses red, green, and blue color values to perturb the normals of the surface at render time, thus giving the appearance of added detail. They can be more accurate than Bump maps, but require specific software such as ZBrush®, Mudbox®, Substance Designer, XnormalTM, and others to generate.
Adjusts the height of the vertices of a surface at render time using a Texture map. Displacement maps differ from Bump or Normal maps in that the geometry is altered by the texture, as opposed to just creating the appearance of detail. Displacement mapping is more complex than using a Bump or Normal map, but the results are more realistic, in particular along the surface's silhouette. Displacement mapping is covered in more detail under the Texture Overview category.
Smooth
Smooths the transition between surface normals. If this option is disabled the edges between the polygons of the surface will be sharp giving the surface a faceted look.
Smooth Shadow Terminator
If enabled, self-intersecting shadows for low polygon objects is smoothed according to the polygon's curvature.
Rounded Edges
Bevels the surface edges at render time without the need to alter or subdivide the geometry. Using this option enhances the object's realism by eliminating sharp edges. The value refers to the radius of the rounded edge. Higher values for this setting produce rounder edges.
Priority
Used to resolve the ambiguity in overlapping surfaces, the surface priority control allows artists to control the order of preference for surfaces. A higher number suggests a higher priority for the surface material, which means it is preferred over a lower priority surface material if a ray enters a higher priority surface and then intersects a lower priority surface while inside the higher priority surface medium.
Emission
Creates a surface that emits light (Mesh emitter). To use this option, connect the Emission input of the Diffuse material to either a Blackbody or Texture emission node. These nodes are covered in more detail under the Texture Overview category, and in Mesh EmittersThe ability for a surface to emit illumination usually described by a Black Body or Texture emission type. under the Lighting Overview category.
Matte
Creates a shadow catching material. When active, the material renders shadows cast onto it, and is transparent everywhere else across a surface.
Writes a mask to the specified custom AOV.
Custom AOV Channel
Determines whether the custom AOV is written to a specific color channel (R, G, or B) or to all the color channels.
Layer
Adds a Material Layer above the base material. See the Material Layers topic in this manual for more details.