anisotropic

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The Anisotropic shader simulates a surface that has microscopic grooves, such as compact discs, some Christmas tree ornaments, brushed metal, or satiny cloth.

An isotropic material (such as Phong or Blinn) has the same specular properties in all directions. An anisotropic material has a distinguishable direction along which the surface is particularly shiny.

Aside from the attributes described here, the Anisotropic shader inherits many attributes from its parents Reflect and Lambert.

Other kinds of shaders you can use:

• For unpolished surfaces, like chalk or matte paint, use a Lambert shader.
• For metallic surfaces, such as brass or aluminum, use a Blinn shader.
• For glossy plastic surfaces, bathroom mouldings, or polymers, use a PhongE shader.

In the table below, important attribute have their names indicated in bold in the description column.

This node is MP safe

lambert, reflect, phongE, phong, blinn, volumeShader, simpleVolumeShader, surfaceShader, displacementShader, layeredShader, useBackground, defaultShaderList, shadingMap

angle, anisotropicReflectivity, fresnelRefractiveIndex, miAngle, miReflectionBlur, miReflectionRays, miReflectivity, miSpecularColor, miSpecularColorB, miSpecularColorG, miSpecularColorR, miSpreadX, miSpreadY, roughness, spreadX, spreadY, tangentUCamera, tangentUCameraX, tangentUCameraY, tangentUCameraZ, tangentVCamera, tangentVCameraX, tangentVCameraY, tangentVCameraZ

Long name (short name)	Type	Default	Flags
tangentUCamera (utan)	float3
u-tangent at sample point
tangentUCameraX (utnx) float 1.0 u-tangent x value
tangentUCameraY (utny) float 1.0 u-tangent y value
tangentUCameraZ (utnz) float 1.0 u-tangent z value
tangentVCamera (vtan)	float3
v-tangent at sample point
tangentVCameraX (vtnx) float 1.0 v-tangent x value
tangentVCameraY (vtny) float 1.0 v-tangent y value
tangentVCameraZ (vtnz) float 1.0 v-tangent z value
spreadX (sprx)	float	13.0
Spread X controls how much the grooves spread out in the "X" direction. It ranges from 0.1 to 100. (The "X" direction is the surface U-direction, rotated counterclockwise by the Angle attribute) When this value is increased, the surface appears smoother in that direction (that is, the specular highlight in that direction shrink). When the value is decreased, the highlight spreads out more in that direction, making the surface appear less smooth.
spreadY (spry)	float	3.0
Spread Y controls how much the grooves spread out in the "Y" direction. It ranges from 0.1 to 100. (The Y direction is perpendicular to the "X" direction --- see the Spread X attribute above.) When this value is increased, the surface appears smoother in that direction (that is, the specular highlight in that direction shrink). When the value is decreased, the highlight spreads out more in that direction, making the surface appear less smooth.
roughness (roug)	float	0.7
Roughness controls the overall roughness of the surface. It ranges from 0.01 to 1.0, with larger values giving a rougher appearance. As this value is increased, the specular highlights are more spread out. This value will also affect the reflectivity of the material, if Anisotropic Reflectivity is turned on.
angle (angl)	float	0.0
Angle defines the "X" and "Y" directions on the surface relative to the surface intrinsic "U" and "V" directions. "X" is the "U" direction, rotated counter-clockwise by the Angle attribute. These "X" and "Y" directions are used by the shader to place the microgrooves that control the anisotropic properties of the shader. This value ranges from 0 to 360 degrees.
fresnelRefractiveIndex (frfi)	float	6.0
Fresnel Refractive Index affects the look of the anisotropic highlight. It does not affect the way light from other objects bends when when passing through the material, if the material is transparent and you are raytracing. As you increase the Fresnel Refractive Index, the highlight becomes brighter. For transparent objects, you may want to set the Fresnel index to match the object's Refractive Index. This will give the most physically accurate result for the highlight.
anisotropicReflectivity (arfl)	bool	true
If Anisotropic Reflectivity is turned on, then the reflectivity of the material is calculated directly from its roughness. If this attribute is turned off, the value in Reflectivity is used instead.
miReflectionBlur (mircb)	float	0
Enable reflection blur by shooting more reflection rays. Blurry reflections require supersampling because a ray direction is not exactly determined anymore. It may deviate (randomly) from the perfect specular direction, within the bounds specified by miReflectionBlur (in angle). A value of zero implies a perfectly specular interaction, a value of 90 a perfectly diffuse reflection or refraction. Values of 10 to 30 are a good starting point
miReflectionRays (mircr)	short	1
Number of reflection rays to use for blurring. miReflectionRays specifies number of rays to use to sample the random deviation. In general more rays are required for more blurry reflections or refractions. Other sampling parameters also affect this setting: per-object samples and the Render Settings sample setting supersample in image space. If you increase any of these two settings, you may be able to reduce the number of rays without loss of quality, but significant performance gain.
miAngle (mia)	float	0
Photon shader angle parameter to control direction of anisotropic feature.
miSpreadX (misx)	float	10
Photon shader x spread parameter to control size of anisotropic feature in x direction.
miSpreadY (misy)	float	5
Photon shader spread parameter to control size of anisotropic feature in y direction.
miSpecularColor (misc)	float3
Photon shader specular color parameter.
miSpecularColorR (miscr) float 0.5 Red component of photon shader specular color.
miSpecularColorG (miscg) float 0.5 Green component of photon shader specular color.
miSpecularColorB (miscb) float 0.5 Blue component of photon shader specular color.
miReflectivity (mirf)	float	0.5
Photon shader reflectivity parameter.