Houdini 20.0 Nodes VOP nodes

MtlX Standard Surface VOP node

A physically-based shader.

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Since 19.0

The MaterialX Standard Surface is a physically-based shader, useful for representing a wide variety of materials.

The MaterialX implementation is based on the Autodesk Standard Surface by Georgiev et al.





Multiplier on the intensity of the diffuse reflection.

Base Color

Color of the diffuse reflection.

Diffuse Roughness

Roughness of the diffuse reflection. Higher values cause the surface to appear flatter and darker.


Specifies how metallic the material appears. At its maximum, the surface behaves like a metal, using fully specular reflection and complex fresnel.



Multiplier on the intensity of the specular reflection.

0, 0.25, 0.5, 0.75, 1.0

Specular Color

Color tint on the specular reflection.

Specular Roughness

The roughness of the specular reflection. Lower numbers produce sharper reflections, higher numbers produce blurrier reflections.

Index of Refraction

Index of refraction for specular reflection. Also sets the refraction for transmissive materials.

Specular Anisotropy

The directional bias of reflected and transmitted light resulting in materials appearing rougher or glossier in certain directions.

Specular Rotation

Rotation of the axis of specular anisotropy around the surface normal.



Transmission of light through the surface for materials such as glass or water. The greater the value the more transparent the material.

Transmission Color

Color tint on the transmitted light.

Transmission Depth

Specifies the distance light travels inside the material before its becomes exactly the transmission color according to Beer’s law.

Transmission Scatter

Not Implemented.

Scattering coefficient of the interior medium. Suitable for a large body of liquid or one that is fairly thick, such as an ocean, honey, ice, or frosted glass.

Transmission Anisotropy

Not Implemented.

The amount of directional bias, or anisotropy, of the scattering.

Transmission Dispersion

Dispersion amount, describing how much the index of refraction varies across wavelengths.

Transmission Roughness

Not Implemented.

Additional roughness on top of specular roughness. Positive values blur refractions more than reflections, and negative values blur refractions less.



The blend between diffuse reflection and subsurface scattering. A value of 1.0 indicates full subsurface scattering and a value 0 for diffuse reflection only.

Subsurface Color

The color of the subsurface scattering effect.

Subsurface Radius

The mean free path. The distance which light can travel before being scattered inside the surface. A vector value is used to specify the the radius for each color component separately.

Subsurface Scale

Scalar weight for the subsurface radius value.

Subsurface Anisotropy

The direction of subsurface scattering. 0 scatters light evenly, positive values scatter forward and negative values scatter backward.



The weight of a sheen layer that can be used to approximate microfibers or fabrics such as velvet and satin.

Sheen Color

The color of the sheen layer.

Sheen Roughness

The roughness of the sheen layer.



The weight of a reflective clear-coat layer on top of the material. Use for materials such as car paint or an oily layer.

Coat Color

The color of the clear-coat layer’s transparency.

Coat Roughness

The roughness of the clear-coat reflections. The lower the value, the sharper the reflection.

Coat Anisotropy

The amount of directional bias, or anisotropy, of the clear-coat layer.

Coat Rotation

The rotation of the anisotropic effect of the clear-coat layer.

Coat Index of Refraction

The index of refraction of the clear-coat layer.

Coat Normal

Input normal for clear-coat layer

Coat Affect Color

Controls the saturation of diffuse reflection and subsurface scattering below the clear-coat.

Coat Affect Roughness

Controls the roughness of the specular reflection in the layers below the clear-coat.

Thin Film

Thin Film Thickness

The thickness of the thin film layer on a surface. Use for materials such as multitone car paint or soap bubbles.

Thin Film Index of Refraction

The index of refraction of the medium surrounding the material.



The amount of emitted incandescent light.

Emission Color

The color of the emitted light.



The opacity of the entire material.

Thin Walled

If true, the surface is double-sided and represents an infinitely thin shell, suiteable for thin objects such as windows, leaves, or paper. Limited Transmission and Subsurface parameters take effect when thin walled geometry is enabled. Thin walled transmission disables refraction.

Only Transmission Color and Transmission Roughness affect thin walled transmission.

Only Subsurface Color affects thin walled subsurface scattering.



Input geometric normal. A worldspace vector in -1->1 range (defaults to current world-space normal).


Input geometric tangent. A worldspace vector in -1->1 range (defaults to current world-space tangent).


The output values can be connected to the output variables in the surface context of the same name.



See also

VOP nodes