Specular Material


The 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. material is used for transparent materials like glass and water (Figure 1).


Figure 1: An object rendered using the Specular materialUsed for transparent materials such as glass and water.


Specular Material Parameters

Reflection - Determines surface reflection strength. Lower values increase the ability to transmit light through the object volume. Reflection and Index Of Refraction work close together to tune Specular material reflectivity.

TransmissionA surface characteristic that determines if light may pass through a surface volume. - Controls how light passes through a transparent surface. Transmission and Index Of Refraction work close together to control surface transparency, and Transmission accepts color or texture input. A value of 1 lets light pass through the surface, making it transparent. To create a mirror surface, set this parameter to a black color, and set Index Of Refraction to 0 (Figure 2). To create colored glass, change the color to something other than white or black. Transmission is different than Opacity - Transmission controls transparency, while Opacity controls surface visibility. You can use Transmission to create reflective glass surfaces, and then use Opacity to create a hole in the surface.

BRDF Model- The BRDF (Bidirectional Reflectance Distribution Function) determines the amount of light that a material reflects when light falls on it. For 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. materials, you can choose from six BRDF models. Specific geometric properties (the micro-facet distribution) of the surface affects each BRDF, which describes the surface's microscopic shape (i.e. micro-facet normals) and scales the brightness of the BRDF's reflections.


Roughness - Determines how much the Specular reflection spreads across the surface. In CG terminology, this is also referred to as reflection blur. A value of 0 simulates a perfect smooth reflective surface, such as a mirror. Increasing the value simulates microfacets in the surface, which causes the reflective highlights to spread. For example, to create the look of worn plastic, increase the Roughness value. This parameter accepts a value, or a Procedural or Image texture map.

Anisotropy - Controls the MaterialThe representation of the surface or volume properties of an object.'s reflectance uniformity. Reflectance changes based on surface orientation, or if the rotation is Anisotropic. If the reflectance is uniform in all directions and doesn't change based on the surface's orientation or rotation, then it is Isotropic. This parameter's default value is 0, which sets the Metallic material as Isotropic. Non-zero values mean the material exhibits Anisotropic reflectance, where -1 is horizontal and 1 is vertical.

Rotation - Controls the Anisotropy effect's orientation.

Spread - Determines the tail spread of the specular BSDF.

Index - Index of Refraction is a value that describes the change in the speed of light as it passes through a medium. As light photons move through surfaces like water, they slow down and change direction. This change appears as the object distorting on the other side of the water's surface. A vacuum's Index Of Refraction (IOR) is 1, and water's IOR is 1.33, meaning light travels 1.33 times faster through a vacuum than water. Most transparent surfaces' IOR is accessible on the internet. Knowing a surface's correct IOR is important for replicating a surface's look in Octane.

Allow Caustics - If enabled, the photon tracing kernel will create caustics for light reflecting or transmitting through the object.

Dispersion - Increasing this value increases the coloration amount and the dispersion in the object's transmission and caustics.

Bump - Creates fine details on material surfaces using a Procedural or Image texture. When you connect a Grayscale image texture to this parameter, light areas appear as protruding bumps, and dark areas appear as indentations. You can adjust the Bump map strength 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 Grayscale image texture node. These attributes are covered in more detail under the Octane TexturesTextures are used to add details to a surface. Textures can be procedural or imported raster files. section of this manual.

Normal - Creates fine details on the surface. A Normal map is a special type of Image texture that uses red, green, and blue color values to perturb the surface normals at render time, 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, or others to generate. To load a full-color Normal map, set the Normal channel to the RGB Image data type. Note that Normal maps take precedence over Bump maps, so you cannot use a Normal map and a Bump map at the same time.

DisplacementThe process of utilizing a 2D texture map to generate 3D surface relief. As opposed to bump and normal mapping, Displacement mapping does not only provide the illusion of depth but it effectively displaces the actual geometric position of points over the textured surface. - Adjusts the surface vertices' height at render time using a Texture map. Displacement maps differs 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, especially along the silhouette of the surface. Displacement mapping is covered in more detail under the Octane Textures section of this manual.

Opacity - Determines what surface parts are visible in the render. Dark values indicate transparent areas, and light values indicate opaque areas. Values between light and dark indicate semi-transparent areas. Lowering the Opacity value fades the object's overall visibility, or you can use a Texture map to vary the surface's opacity. For example, if you want to make a simple polygon plane look like a leaf, you connect a black-and-white image of the leaf's silhouette to 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. shader's Opacity channel. When you use an Image texture map, set the Data type to Alpha Image if the image has an Alpha ChannelA greyscale image used to determine which areas of a texture map are opaque and which areas are transparent., or Grayscale image for black-and-white images, to load an image for setting transparency. Use the image's Invert checkbox to invert the transparency regions.

Smooth - Smooths the transition between surface normals. If this option is disabled, the edges between the polygons of the surface are sharp, giving the surface a faceted look.

Smooth Shadow Terminator - If enabled, self-intersecting shadows are smoothed according to the polygon's curvature.

Round Edges - Smooth sharp edges during render time. When the Round Edges node is connected to this input, the following attributes are available:

Medium - Octane has five types of mediums which can be used to create translucent surfaces.

Fake Shadows - Activates the Architectural glass option for all Meshes sharing that Material. When enabled, Specular materials exhibit Architectural glass characteristics with its transparent feature, allowing light to illuminate enclosed spaces or frame an exterior view.

Affect Alpha - Lets refractions affect the Alpha Channel, as long as you enable the Alpha Channel in the Render settings’ Kernel parameters.

Thin Wall - If the geometry attached to the material is a single-sided plane, this parameter lets the rays bounce off the surface right away instead of entering the medium.

Film Width - Simulates the look of thin film material on a surface, like creating a rainbow color effect that appears on an oil slick's surface. Larger values increase the effect's strength.

Film Index - Controls the film's IOR by adjusting its visible colors.

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.

Material Layer - Adds a Material Layer above the base material, which provides greater flexibility for mixing and blending multiple surface characteristics.

Custom AOV - 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.

Virtual Material - Gives particles random materials. The main material is assigned to the particles. After that, you can create any number of additional materials by adding them to the MaterialsA set of attributes or parameters that describe surface characteristics. List. The particles are assigned materials according to the Virtual Material type chosen. If you select the Non-Permanent Object Material checkbox, materials will not stick to the particles.

Maya Viewport Rollout

Textures Resolution (PX) - Assigns a resolution to the Texture. Default setting is 1, which represents a 1 x 1 square. The maximum setting is 1024.

Preview Plane Size (M) - Adjusts the Octane Material preview plane's size, with the default value measured in meters.

Texture Quality (SPP) - The number of samples rendered per pixel. Higher values give finer details at the expense of rendering speed.

Shininess (VP2.0 Only) - Renders roughness in the Viewport. A value of 0 makes the texture totally shiny, and a value of 8 makes the texture totally rough.

Rebuild Textures - Refreshes the Viewport after you adjust any of the parameters in this section.

Swatch Quality (SPP) - The number of samples rendered per pixel on the native Swatch material in Maya®.