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Clarisse 5.5 Reference Guide

The Autodesk Standard Surface is a multipurpose physical material compatible with the Autodesk Standard Surface Material (ASSM) specification. This material which is already available in Autodesk Arnold, allows you to accurately mimic most real world materials like plastics, metals, liquids, fabric, glass or skin from a reduced set of parameters. For more information about ASSM, please refer to https://autodesk.github.io/standard-surface/

 

Autodesk Standard Surface used to lookdev the whole scene

Autodesk Standard Surface used to lookdev the whole scene

 

Note

All the renders in this page are rendered with Caustic Sharpness to 100%

 

Autodesk Standard Surface material on the sphere with default settings

Autodesk Standard Surface material on the sphere with default settings

 

Note

The Autodesk Standard Surface Material doesn't guaranty a 100% look consistency across the different rendering engines implementing it. While you can expect to get extremely close results, some features such as multiple scattering or subsurface scattering are likely have different implementations leading to render differences.

Base

The Base set of attributes controls the base layer of the material. It is defined by a Oren-Nayar diffuse reflection mixed with a GGX conductor. The blending between the two models is controlled using Metalness attribute which defines the metallic property of the material. The final color of the base layer is defined by Base Color which is then multiplied by Base Weight.

Attribute

Description

Base Weight

Set the intensity of the base layer.

Base Color

Set base diffuse and reflection color.

Diffuse Roughness

Set the roughness of the diffuse layer.

Metalness

Set the metalness property of the material where a value of 0.0 is a pure dielectric (glass, plastic, leather...) and 1.0 a metal conductor (copper, gold, silver).

Diffuse Roughness

Diffuse Roughness defines the roughness of the diffuse layer. The diffuse BRDF is an Oren-Nayar where a roughness of 0.0 corresponds to a pure Lambertian surface and high roughness values mimic rough surface such as concrete or sand.

 

Diffuse Roughness 0.0%

Diffuse Roughness 0.0%

Diffuse Roughness 25.0%

Diffuse Roughness 25.0%

Diffuse Roughness 50.0%

Diffuse Roughness 50.0%

Diffuse Roughness 75.0%

Diffuse Roughness 75.0%

Diffuse Roughness 100.0%

Diffuse Roughness 100.0%

Metalness

Metalness defines how metallic the material is. A non metallic material (defined by a Metalness of 0.0) behaves like pure dielectrics such as glass, plastic, leather... Pure metallic materials on the other hand are defined by a Metalness of 1.0 in which case react like metal conductors such as copper, gold, or silver... Any in-between values simulate hybrid materials that are a mix of dielectric and conductor. Such materials are quite common in real world like you can find on base coat of metallic car paints, that are a mix of a solid paint (reacting like a dielectric material) and metal flakes (conductors).

 

Metalness 0.0%

Metalness 0.0%

Metalness 25.0%

Metalness 25.0%

Metalness 50.0%

Metalness 50.0%

Metalness 75.0%

Metalness 75.0%

Metalness 100.0%

Metalness 100.0%

Specular

The Specular set of attribute controls the properties of the conductor/metallic layer.

Attribute

Description

Specular Weight

Set the intensity of the reflection.

Specular Color

Set the reflection color. When the material is fully metallic Specular Color only tints the reflection at glancing angles

Specular Roughness

Set the roughness of the reflection.

Specular IOR

Set the index of refraction of the dielectric material. This attribute is completely ignored when the material is fully metallic.

Specular Anisotropy

Set the anisotropy of the reflection

Specular Rotation

Set the direction of the anisotropy

Specular Color

The Specular Color attribute allows you to tint reflection by the specified color. The actual resulting color of the reflection is multiplication between Base Color, Specular Color and Specular Weight. When the material is metallic, Specular Color only tints reflections at glancing angles.

 

Blue Specular Color and Metalness 0.0%

Blue Specular Color and Metalness 0.0%

When Metalness is at 100.0% the only glancing angles are colored

When Metalness is at 100.0% the only glancing angles are colored

Specular Roughness

Specular Roughness defines the roughness of the metallic layer. The rougher the surface is, the softer the specular reflection. Perfect mirrors should have a roughness of 0% and perfectly rough (diffuse) surface should have a roughness of 100%.

 

Specular Roughness 0.0%

Specular Roughness 0.0%

Specular Roughness 25.0%

Specular Roughness 25.0%

Specular Roughness 50.0%

Specular Roughness 50.0%

Specular Roughness 75.0%

Specular Roughness 75.0%

Specular Roughness 100.0%

Specular Roughness 100.0%

Specular IOR

Specular IOR defines index of refraction of the dielectric which controls intensity of the reflection according to the fresnel. Please note that Specular IOR has absolutely no effect when the material is fully metallic (Metalness set to 100%).

 

Specular IOR 1.0

Specular IOR 1.0

Specular IOR 1.25

Specular IOR 1.25

Specular IOR 1.5

Specular IOR 1.5

Specular IOR 1.75

Specular IOR 1.75

Specular IOR 2.0

Specular IOR 2.0

Specular Anisotropy and Rotation

Specular Anisotropy and Specular Rotation allow you to simulate brushed materials. Specular Anisotropy controls how much the specular highlight is stretched along the axis and Specular Rotation specifies the major direction of microfacets (0% gives no direction, 50% gives 90 degrees rotation and 100% gives 180 rotation). Specular Rotation expects a black and white texture that defines the direction of the anisotropy. Please also note that it is highly recommended to disable image filtering (setting it to Nearest Neighbor) when using texture maps to control Rotation to avoid any interpolation artifacts.

 

Anisotropy rotation map

Anisotropy rotation map

 

Textured Specular Rotation

Textured Specular Rotation

 

Note

The axis of the anisotropy is controlled by the first UV of the geometry when available. When no UV is available the anisotropy uses a local axis which doesn't guaranty continuity. For best results it is recommended to use a UV map with as few discontinuities (seams) as possible.

Transmission

The Transmission set of attribute controls how transmissive the material is. The roughness and index of refraction of the transmission are both linked to Specular Roughness and IOR respectively. It is however possible to add or remove extra roughness to the transmission using Transmission Extra Roughness attribute.

Attribute

Description

Transmission Weight

Set the intensity of the transmission.

Transmission Color

Set the transmission color.

Transmittance Depth

Set the transmittance depth.

Transmission Scatter

Set the scattering color within the inner volume.

Transmission Scatter Anisotropy

Control the anisotropy of the medium scattering.

Transmission Extra Roughness

Set positive or negative extra roughness for the transmission.

Transmission Weight

It is possible to add transmissive property to the material by using the Transmission Weight attribute. Please note that the Autodesk Standard Surface Material does not provide a physically correct dielectric material when it is both reflective and refractive.

 

Transmission Weight 0.0%

Transmission Weight 0.0%

Transmission Weight 25.0%

Transmission Weight 25.0%

Transmission Weight 50.0%

Transmission Weight 50.0%

Transmission Weight 75.0%

Transmission Weight 75.0%

Transmission Weight 100.0%

Transmission Weight 100.0%

Transmission Color

The Transmission Color attribute defines the color of the transmission multiplied by Transmission Weight.

 

50% White Transmission Color

50% White Transmission Color

50% Blue Transmission Color

50% Blue Transmission Color

Transmission Extra Roughness

The Transmission Extra Roughness attribute is an artistic control that allows you to add or remove roughness to the value defined by Specular Roughness. This is very useful to unlink the roughness value of the refraction from the reflection. Please note that final transmission roughness value is always normalized (between 0 and 1).

 

Specular Roughness 0.0% Transmission Extra Roughness 0.0%

Specular Roughness 0.0% Transmission Extra Roughness 0.0%

Transmission Extra Roughness 25.0%

Transmission Extra Roughness 25.0%

Specular Roughness 25.0% Transmission Extra Roughness 0.0%

Specular Roughness 25.0% Transmission Extra Roughness 0.0%

Transmission Extra Roughness -25.0%

Transmission Extra Roughness -25.0%

Subsurface

The Subsurface set of attributes simulates the effect of light penetrating a translucent surface that is scattered multiple times inside before exiting the surface. It is used to simulate the translucency component of wax, skin, marble etc... The material approximates a homogeneous volume on which properties are defined from the entry point and the subsurface parameters.

Note

Fully transmissive materials can't define a subsurface layer.

Attribute

Description

Subsurface Mode

Set the engine used to simulate subsurface scattering.

Subsurface Weight

Set the weight of the subsurface.

Subsurface Color

Set the color of the subsurface.

Subsurface Radius

Set the radius of the subsurface. The bigger the value, the more light penetrates the medium.

Subsurface Scale

Scale applied to Subsurface Radius.

Subsurface Anisotropy

Set the anisotropy of the medium scattering.

Subsurface Group

Set a surface group The Subsurface Group attribute enables the user to specify the name of a group among which illumination propagates between materials with subsurface.

Subsurface Mode

The Subsurface Mode attribute allows you to choose between two techniques to approximate subsurface scattering:

Model

Description

Diffusion

Diffusion aggregates light paths around the entry point of the surface and integrate their contribution. Diffusion is an efficient technique which works really well when mean free path is smaller than the geometric details of the geometry. This technique is faster to render than Random Walk.

Random Walk

Random Walk path traces light paths inside the surface making it a better approximation for thin surfaces which is more expensive and slower to compute than Diffusion. Random Walk approximates more accurately the scattering inside the medium and captures more realistic fine geometric details of the geometry that are missed by the Diffusion. Since it requires more samples, it is also more expensive and slower to compute than Diffusion.

 

Diffusion Subsurface Mode 

Diffusion Subsurface Mode 

In Random Walk the material manages to capture small geometric details

In Random Walk the material manages to capture small geometric details

Larger Subsurface Scale using Diffusion fails resolving fine details

Larger Subsurface Scale using Diffusion fails resolving fine details

Witth such scale the difference is even more obvious in Random Walk

Witth such scale the difference is even more obvious in Random Walk

 

Both Diffusion and Random Walk make the assumption that the underlying geometry defines an enclosed volume. If the geometry isn't defining an enclosed volume (such as how leaves and grass blades are usually modeled) you must enable the Thin Walled attribute so that SSS works properly since enabling Thin Walled falls back to an alternate method using diffuse transmission which is well suited for such geometries.

 

Thin Walled Subsurface to simulate a translucent sheet of paper made of a single polygon

Thin Walled Subsurface to simulate a translucent sheet of paper made of a single polygon

 

Subsurface Color

The Subsurface Color attribute defines the color of the subsurface scattering reflected from below surface.

Subsurface Radius

Subsurface Radius defines the maximum distance light can penetrate and scatter below the surface defined as a color. This attribute actually defines the average distance of each wavelength (RGB) for which light can be absorbed and scattered by the medium. Increasing this value directly impacts the translucency of the material. This attribute internally defines the Mean Free Path (MFP) which corresponds to the average distance light can traveling through the surface before exiting.

Subsurface Scale

The Subsurface Scale is simply a scale multiplying the Subsurface Radius.

 

Chicken 1 preset with Subsurface Scale set to 0.01

Chicken 1 preset with Subsurface Scale set to 0.01

When Subsurface Scale is set to 0.25, lights penetrates deeper in the material

When Subsurface Scale is set to 0.25, lights penetrates deeper in the material

 

Note

It is highly recommended to set Subsurface Mode to Random Walk when Subsurface Radius is larger than the thickness of the geometry since Diffusion sampling technique is going to fail capturing geometric details that are smaller than the radius.

Subsurface Anisotropy

The Subsurface Anisotropy attribute controls the anisotropy of the medium scattering. By default, light is scattered isotropically (by the same quantity in all directions). Positive Anisotropy values bias the scattering forward in the direction of the light while negative ones backward toward the light.

 

Subsurface Anisotropy -100.0%

Subsurface Anisotropy -100.0%

Subsurface Anisotropy -50.0%

Subsurface Anisotropy -50.0%

Subsurface Anisotropy 0.0%

Subsurface Anisotropy 0.0%

Subsurface Anisotropy 50.0%

Subsurface Anisotropy 50.0%

Subsurface Anisotropy 100.0%

Subsurface Anisotropy 100.0%

 

Note

It is recommended to use the Random Walk technique when specifying positive values of anisotropy since it will lead to a loss of energy using Diffusion.

Coat

The Coat set of attributes allows you to define a thin dielectric layer on top of all other layers to simulate clear coat.

 

Coat Weight at 0%

Coat Weight at 0%

Coat Weight at 100%

Coat Weight at 100%

 

Attribute

Description

Coat Weight

Set the weight of the coat layer

Coat Color

Set the color of the coat.

Coat Roughness

Set the roughness of the coat.

Coat Ior

Set the index of refraction of the coat.

Coat Anisotropy

Set the anisotropy of the coat. Coat Anisotropy works the same way as Specular Anisotropy

Coat Rotation

Set the anisotropy rotation of the coat. Coat Rotation works the same way as Specular Rotation

Coat Normal

Set the normal of the coat layer.

Coat Color

The Coat Color defines the color of the coat layer. Please note that specified color is filtered before being transmitted to the layers below. If you specify a pure red coat color while the layer below is blue, the material won't be able to reflect blue since only red is transmitted below.

 

No Coat layer

No Coat layer

Coat Color set to (1.0, 1.0, 1.0)

Coat Color set to (1.0, 1.0, 1.0)

Coat Color set to (0.4, 0.448, 1.0)

Coat Color set to (0.4, 0.448, 1.0)

Coat Color set to (0.0, 0.0, 1.0)

Coat Color set to (0.0, 0.0, 1.0)

Coat Color set to (1.0, 1.0, 0.0)

Coat Color set to (1.0, 1.0, 0.0)

Coat Roughness

The Coat Roughness allows you to specify the roughness of the coat independently from the base surface.

 

Coat Roughness 0.0%

Coat Roughness 0.0%

Coat Roughness 25.0%

Coat Roughness 25.0%

Coat Roughness 50.0%

Coat Roughness 50.0%

Coat Roughness 75.0%

Coat Roughness 75.0%

Coat Roughness 100.0%

Coat Roughness 100.0%

Coat Ior

The Coat Ior allows you to specify an index of refraction for the coat independently from the base surface.

 

Coat Ior 1.0

Coat Ior 1.0

Coat Ior 1.25

Coat Ior 1.25

Coat Ior 1.5

Coat Ior 1.5

Coat Ior 1.75

Coat Ior 1.75

Coat Ior 2.0

Coat Ior 2.0

Coat Normal

The Coat Normal allows you to specify a surface normal for the coat independently from the base surface. This is very useful to simulate scratches, water drops or a very glossy clear coat layer on top of a very rough material.

 

Coat Normal using Geometry Normal (no bump)

Coat Normal using Geometry Normal (no bump)

Coat and Base using same normal

Coat and Base using same normal

Bump only applied to Coat Normal

Bump only applied to Coat Normal

Sheen

The Sheen set of attributes allows you to simulate an energy conservative layer made of microfibers such fabric, velvet, peach fuzz...

Attribute

Description

Sheen Weight

Set the weight of the sheen.

Sheen Color

Set the color of the sheen.

Sheen Roughness

Set the roughness of the sheen which randomizes the direction of the microfibers.

 

Sheen Roughness 0.0%

Sheen Roughness 0.0%

Sheen Roughness 25.0%

Sheen Roughness 25.0%

Sheen Roughness 50.0%

Sheen Roughness 50.0%

Sheen Roughness 75.0%

Sheen Roughness 75.0%

Sheen Roughness 100.0%

Sheen Roughness 100.0%

Emission

The Emission set of attributes allows you to define the emissive property of the material to simulate incandescence.

Attribute

Description

Emission Weight

Set the weight of the emission.

Emission Color

Set the color of the emission.

 

No Emission

No Emission

Emission Enabled

Emission Enabled

Thin Film

The Thin Film set of attributes simulates the effect of thin film interference occurring on some surfaces such as soap bubbles, oil puddles, coated lens/glass, insect wings etc...

Attribute

Description

Thin Film Thickness

Set the thickness of the thin film layer in nm (nanometers).

Thin Film Ior

Set the index of refraction of the thin film medium.

 

Thin Film Thickness 300

Thin Film Thickness 300

Thin Film Thickness 350

Thin Film Thickness 350

Thin Film Thickness 400

Thin Film Thickness 400

Thin Film Thickness 450

Thin Film Thickness 450

Thin Film Thickness 500

Thin Film Thickness 500

Thin Film Ior 1.0

Thin Film Ior 1.0

Thin Film Ior 1.25

Thin Film Ior 1.25

Thin Film Ior 1.5

Thin Film Ior 1.5

Thin Film Ior 1.75

Thin Film Ior 1.75

Thin Film Ior 2.0

Thin Film Ior 2.0

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