Standard Surface

asStandardSurface

A physically based material with a dielectric coating with absorption, and a substrate with optional subsurface scattering, refraction, volumetric absorption.


Parameters


Diffuse Parameters

Diffuse Weight
A scaling factor for the diffuse BRDF.
Diffuse Color
The surface color.
Diffuse Roughness
The diffuse roughness, with a value of 0, it corresponds to a Lambert diffuse term. Higher values flatten the appearance of the surface, giving it a chalky look. [1]

Subsurface Parameters

Subsurface Weight
A weighting factor for the subsurface scattering term.
Subsurface Mean Free Path (MFP)
Color controling how far light enters and travels within the medium.
Subsurface MFP Scale
Overall scaling factor for the MFP color, which is expected in [0,1] range. Values above 1.0 are possible, resulting in increased translucency appearance.

Advanced

Subsurface Profile

The diffusion profiles to use in the BSSDRF [2]. This parameter can take the following values:


Translucency Parameters

Translucency Weight
Controls the amount of thin translucency of the object.
Translucency Color
Color affecting the thin translucency term.

Specular Parameters

Specular Color
Overall specular tint for the specular BRDF.
Specular Roughness
The apparent surface roughness affecting the specular highlights.

Fresnel

Fresnel Type

Allows the user to choose the specular mode, of a dielectric such as plastic or glass, or of a conductor or metal.

Note

To use refraction, the mode must be set to dielectric and the index of refraction set. When in conductor mode, the face tint and edge tint parameters are used to derive the complex index of refraction instead [Gulbrandsen2014Fresnel] and no refraction is used.

IOR
The index of refraction for the dielectric mode.
Facing Tint
The reflectance at normal incidence.
Edge Tint
Reflectance at grazing incidence.

Anisotropy

Anisotropy Amount
Overall intensity of the anisotropy effect, with a value of 0.0 representing a isotropic specular highlight.
Anisotropy Angle
Rotation angle for the anisotropic highlight in [0,1], mapping a rotation from 0 to 360 degrees.
Anisotropy Map
Also known as tangent field, encodes the anisotropy directions along X and Y in the Red and Green or Red and Blue channels of the image. Appleseed expects values encoded in the Red and Green channels.

Refraction Parameters

Refraction Amount
Intensity of the refraction, only taking place when Fresnel is dielectric [Walter2007].
Refraction Tint
Overall tinting factor, it affects the BTDF equally, unlike volumetric absorption.

Volumetric Absorption

Absorption Depth
Sets the depth at which full absorption takes place. Low values result in dense absorbing materials, high values in transparent appearance ones.
Absorption Color
The color used for the volumetric absorption.

Coating Parameters

Coating Reflectivity
Intensity of specular highlights on the coating.
Coating Roughness
Apparent surface roughness of the coating specular highlights.
Coating IOR
Index of refraction of the coating layer, usually a dielectric, with values around 1.5.

Coating Absorption

Coating Thickness
Thickness of the coating layer, controlling the intensity of coating absorption, with 0 being no absorption, 1 being full absorption.
Coating Absorption
Absorption color for the coating, white has no effect, black absorbs fully.

Incandescence Parameters

Incandescence Amount
The overall intensity of the incandescence effect.
Incandescence Type
Color choice for incandescence color, with constant taking as input the user-set value, and blackbody using a blackbody radiator. [3]
Incandescence Color
Incandescence color, ignored in blackbody mode.
Temperature
Temperature in Kelvin degrees, ignored in constant mode.

Options

Area Normalize EDF
Normalize by the object area, so that object deformations keep the incandescence energy. If unset, deforming the object will retain the incandescence color.
Tonemap EDF
Tonemaps the potentially high energy result of the blackbody radiator into the [0,1] range. Disabled by default.

Note

The tonemap EDF option has effect only when incandescence type is set to blackbody.


Transparency Parameters

Transparency
Affects the presence of an object. When transparency is binary (full opaque or full transparent, with no in-between values), appleseed alpha masks should be used instead.

Bump Parameters

Coating Normal
The bump normal for the coating layer.
Substrate Normal
The bump normal for the substrate.

Matte Parameters

Enable Matte
Flag toggling matte holdouts on or off.
Matte Opacity
Overall scaling factor for the matte, from solid black to normal.
Matte Opacity Color
Color for the matte.

Advanced Parameters

SSS Ray Depth
Maximum number of ray bounces for the subsurface scattering term.
SSS Threshold
Defines the distance light has to travel within the medium to start the subsurface scattering effect. A low enough mean free path value will have a visually negligible difference from a diffuse term. This parameter sets the threshold at which the subsurface calculations start, instead of the ordinary diffuse term.
Maximum Ray Depth
The maximum number of bounces a ray is allowed to travel.

Outputs

Output Color
The final result color.
Output Transparency
The final transparency color.
Output Matte Opacity
The final matte opacity. Note that OSL holdout is unsupported at the moment.

Screenshots


Footnotes

[1]The diffuse BRDF used is the Oren-Nayar BRDF [Oren:1994:GLR:192161.192213]
[2]See also Extending the Disney BRDF to a BSDF with Integrated Subsurface Scattering for details.
[3]https://en.wikipedia.org/wiki/Black-body_radiation

References

[Chr15]Per H. Christensen. An approximate reflectance profile for efficient subsurface scattering. In ACM SIGGRAPH 2015 Talks, SIGGRAPH ‘15, 25:1–25:1. New York, NY, USA, 2015. ACM. URL: http://doi.acm.org/10.1145/2775280.2792555, doi:10.1145/2775280.2792555.
[dEonLE07]Eugene d’Eon, David Luebke, and Eric Enderton. Efficient rendering of human skin. In Proceedings of the 18th Eurographics Conference on Rendering Techniques, EGSR‘07, 147–157. Aire-la-Ville, Switzerland, Switzerland, 2007. Eurographics Association. URL: http://dx.doi.org/10.2312/EGWR/EGSR07/147-157, doi:10.2312/EGWR/EGSR07/147-157.
[Gul14]Ole Gulbrandsen. Artist friendly metallic fresnel. Journal of Computer Graphics Techniques (JCGT), 3(4):64–72, December 2014. URL: http://jcgt.org/published/0003/04/03/.
[MHD16]Johannes Meng, Johannes Hanika, and Carsten Dachsbacher. Improving the dwivedi sampling scheme. Comput. Graph. Forum, 35(4):37–44, jul 2016. URL: https://doi.org/10.1111/cgf.12947, doi:10.1111/cgf.12947.
[ON94]Michael Oren and Shree K. Nayar. Generalization of lambert’s reflectance model. In Proceedings of the 21st Annual Conference on Computer Graphics and Interactive Techniques, SIGGRAPH ‘94, 239–246. New York, NY, USA, 1994. ACM. URL: http://doi.acm.org/10.1145/192161.192213, doi:10.1145/192161.192213.
[WMLT07]Bruce Walter, Stephen R. Marschner, Hongsong Li, and Kenneth E. Torrance. Microfacet models for refraction through rough surfaces. In Proceedings of the 18th Eurographics Conference on Rendering Techniques, EGSR‘07, 195–206. Aire-la-Ville, Switzerland, Switzerland, 2007. Eurographics Association. URL: http://dx.doi.org/10.2312/EGWR/EGSR07/195-206, doi:10.2312/EGWR/EGSR07/195-206.