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titleDiffuse Parameters

Diffuse Parameters

The diffuse parameters control the look of basic diffuse reflection. These are often used to define primary color attributes for opaque objects; wood textures, label text, polka dots, or more, you can find them all connected here.

Gain

Gain is the weight applied to the diffuse parameters. You may also drive this with another pattern to show things like fading or wetness (where liquid darkens a surface).



Color

Color is typically where textures or patterns are connected to create color for opaque objects. This is where a wood color texture would go, for example.



Roughness

Diffuse roughness is how you would simulate a powdery surface like dried clay or dust.

 

 

Bump

Normal to use for the diffuse illumination. If this is not set, it will use the global bump normal specified in the Properties section near the bottom of this page.

 

 

Double Sided

If on, illuminate both sides of the surface for this diffuse lobe, that is, this will illuminate the surface whose normal is pointing away from the camera as well.

 

 

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titleSpecular Parameters

Specular Parameters

The specular parameters control speculal reflection. This is where you might define how shiny or reflective an object is. Is it plastic, a polished marble table, or  is it a mirror?

Specular Model

Select which specular model to use: Beckmann or Ggx. Ggx may be preferred here for its "tail", or how the highlight has a soft fade from the center reflection of a lightsource.

 

 

Face Color

Specular color at facing angle (0 degree incidence). Note that there is no separate gain control. To control the specular "gain", simply adjust the color value or connect it to a PxrExposure node.

 

 

Edge Color

Specular color at the glancing angle (90 degree incidence). To control the edge specular "gain", simply adjust the color value or connect it to a PxrExposure node.

 

 

Fresnel Exponent

Specular fresnel curve exponent. Lower numbers reduces the effect of Face Color while increasing the effect of Edge Color. Higher numbers reverse this. If your face and edge colors are the same, then there is no visible effect.

 

 

Roughness

Specular roughness. A greater value produces rougher or "blurry" specular reflection. At 1.0 it resembles a diffuse surface and at 0.0 it's a perfectly clear reflection. Most objects will be realistic somewhere in between these values. Texturing this value may give you interesting effects like smudges, greasy fingerprints, and worn surfaces.

 

 

Anisotropy

Controls the shape of the specular highlights and reflections. 0 means isotropy which produces the regular circular specular highlight. Values from -1.0 to 1.0 produce the range of ellipses (stretching) from wide to tall.

By default, the direction of anisotropy is controlled by the model texture parameters. If the Shading Tangent is specified, it is used instead.

 

 

Shading Tangent

Controls the anisotropy direction. Only valid when it is connected to a pattern. This is useful for making brushed metals.

 

 

Bump

Normal to use for the specular illumination. If this is not set, it will use the global bump normal specified in the Properties near the bottom of this page.

 

 

Double Sided

If on, illuminate on both sides of the surface for this specular lobe, that is, this will illuminate the surface whose normal is pointing away from the camera as well.

 

 

Rough Specular

Similar to Specular parameters except it has a larger default roughness which is 0.6. This layer is intended for use with higher roughness settings than the Specular lobe above.

 

 

 

 

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titleClear Coat Parameters

Clear Coat

Clear coats are great for making a top glazed layer found in coated objects or paints like car paint. While roughness is available, this layer is intended for low amounts of roughness.

Specular Model

Select which specular model to use: Beckmann or Ggx. Again, Ggx might be preferred for its "tail" or fade from the center highlight of reflected light sources.

 

 

Face Color

Specular color at facing angle (0 degree incidence). Note that there is no separate gain control. To control the specular "gain", simply adjust the color value or connect it to a PxrExposure node.

 

 

Edge Color

Specular color at the glancing angle (90 degree incidence). To control the edge specular "gain", simply adjust the color value or connect it to a PxrExposure node.

 

 

Fresnel Exponent

Specular fresnel curve exponent. Lower numbers reduces the effect of Face Color while increasing the effect of Edge Color. Higher numbers reverse this. If your face and edge colors are the same, then there is no visible effect.

 

 

Roughness

Specular roughness. A greater value produces rougher or "blurry" specular reflection. At 1.0 it resembles a diffuse surface and at 0.0 it's a perfectly clear reflection. Most objects will be realistic somewhere in between these values. Texturing this value may give you interesting effects like smudges, greasy fingerprints, and worn surfaces.

 

 

Anisotropy

Controls the shape of the specular highlights and reflections. 0 means isotropy which produces the regular circular specular highlight. Values from -1.0 to 1.0 produce the range of ellipses (stretching) from wide to tall.

By default, the direction of anisotropy is controlled by the model texture parameters. If the Shading Tangent is specified, it is used instead.

 

 

Shading Tangent

Controls the anisotropy direction. Only valid when it is connected to a pattern. This is useful for making brushed metals.

 

 

Bump

Normal to use for the clear coat illumination. If this is not set, it will use the global bump normal specified in the Properties near the bottom of the page. Setting this separately can produce a "glazed" effect where you have a bumpy clearcoat above a smooth surface.

 

 

Double Sided

If on, illuminate on both sides of the surface for this clear coat lobe, that is, this will illuminate the surface whose normal is pointing away from the camera as well.

 

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titleReflection & Refraction Parameters

Reflection/Refraction Parameters

Refraction Gain

Refraction gain.

Reflection Gain

Reflection gain.

Refracton Color

Refraction color.

Roughness

Refraction and reflection roughness.

Refractive Index

Index of refraction.

Thin

If on, correctly split energy according to Refractive Index between reflection and refraction, but do not bend the ray in refraction (simulating a double pane of glass with a single pane).

Interior Parameters

Single Scatter Albedo

Single scatter albedo. Connect this to a 3D pattern to control the intensity of the scattering.

Single Directionality

Controls the directionality of the scattering.0 : isotropic1 : forward-1 : backward

Extinction

Extinction color. Connect this to a 3D pattern to control the density of the interior.

Integration Mode

Control volume integration type:Ray MarchingRatio Tracking. Unused, this is currently internal to the PixarAnimation Studios.

Min Extinction Color

Minimum extinction color.

Max Extinction Color

Maximum extinction color.

Step Size

Ray marching step size. Step size is based on the resolution of the 3D pattern that is connected. Inadequate step size will produce artifacts.

Max Steps

Max number of steps.

 

 

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titleGlobal Properties Parameters

Properties Parameters

This section provide global controls for the entire material. For example, if a Bump is only supplied here, it applies to all the above lobes. Presence is also a global parameter that will mask out or "cutout" all the lobes as-if the object isn't present where the mask has a value of 0.0

Bump

Normal to use for all illumination unless it is overridden by the individual lobe's bump normal.

Presence

Connect a mask here to apply a cutout pattern to your object. Presence is defined as a binary (0 or 1) function that can take on continuous values to anti-alias the shape. Useful for creating leaves and other thin, complex shapes.

Info

This value should be either 0 or 1. A value between 0 and 1 will produce unwanted noise!

Presence Cached

Specify whether presence is cached or not.

Shadow Mode

Shadow opacity computation mode:

  • Shader and shadow color
  • Shadow color only

Shadow Color

Specify shadow color. This parameter is useful for faking a shadow color for art direction purposes.

Specular Energy Compensation

Applies fresnel energy compensation to diffuse and subsurface illumination lobes. A value of 1.0 attempts to fully balance those results by darkening them against the specular and rough specular illumination responses.

Specular and Rough Specular roughness are also taken into account. The effect fades off as specular face or edge color approaches 1.0, so metals can add a diffuse baseline color.

Clearcoat Energy Compensation

Applies fresnel energy compensation to all lobes other than clearcoat itself. A value of 1.0 attempts to fully balance those results by darkening them against the clearcoat illumination response.

Clearcoat roughness is also taken into account. The effect fades off as clearcoat face or edge color approaches 1.0, so metals can add a diffuse baseline color.

Irradiance Tint

A tint applied to illumination before being scattered by subsurface or single scatter.

Unit Length

Subsurface and single scatter unit length. It is a multiplier on Mean Free Path Distance. Mean Free Path Distance is often measured in millimeters. If the scene is modeled in some other scale, Unit Length should be set accordingly. The default value of 0.1 is appropriate for scenes modeled in centimeters (the default in Maya) and Mean Free Path Distance measured in millimeters.

 

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