The Surface Texture Parameters Glossary provides information on many of the surface roughness parameters that are commonly used in industry and research. It includes definitions of each parameter, along with information about when they are used, and details on how to apply the parameters in real-work applications.
Click on a parameter below to view its details, or click on the category to view descriptions of all parameters in the grouping. You can also view parameters by Name or Symbol.
3D Hybrid Parameters
Sdq ( Root Mean Square Surface Slope )
Material Ratio - Bearing Area
Sdc(mr) ( Inverse Areal Material Ratio )
Smr(c) ( Areal Material Ratio )
SMr1 ( Peak Material Portion )
SMr2 ( Valley Material Portion )
Spk/Sk ( Reduced Peak Height to Core Roughness Ratio )
Spk/Svk ( Reduced Peak Height to Reduced Valley Depth Ratio )
Stylus (X,Y) Rk ( Core Roughness Along X, Y )
Stylus (X,Y) Rpk ( Reduced Peak Height Along X, Y )
2D Stylus
Stylus (X,Y) Pc or Rpc ( Peak Density Along X,Y )
Stylus (X,Y) Ra ( Average Roughness Along X, Y )
Stylus (X,Y) Rsm ( Mean Profile Spacing Along X,Y )
Stylus (X,Y) Rt ( Maximum Profile Height Along X, Y )
Stylus (X,Y) Rz ( Average Maximum Profile Height Along X, Y )
Stylus (X,Y) Δq ( Root Mean Square Slope Along X,Y )
Stylus (X,Y) λq ( Root Mean Square Profile Wavelength Along (X, Y) )
Stylus X Pc/ Stylus Y Pc ( Stylus Pc Ratio )
Stylus X Ra/Stylus Y Ra ( Stylus Ra Ratio )
Stylus X Rz/Stylus Y Rz ( Stylus Rz Ratio )
The definitions and more detailed discussions of the various surface texture parameters may be found in the following references:
ISO 25178-2:2009 “Geometrical product specifications (GPS) – Surface texture: Areal Part 2 Terms, definitions and surface texture parameters.
ISO 25178-3:2009 “Geometrical product specifications (GPS) – Surface texture: Areal Part 3 Specification operators.
ISO 1302:2002 “Geometrical product specifications (GPS)- Indication of surface texture in technical product documentation.
ANSI/ASME B46.1-2002 “Surface Texture (Surface Roughness, Waviness and Lay),” American Society of Mechanical Engineers, 2002.
ISO 4287:1997 “Geometrical Product Specifications (GPS) – Surface texture: Profile method – Terms, definitions and surface texture parameters”
ISO 13565-2:1996 “Geometrical Product Specifications (GPS) – Surface texture: Profile method; Surfaces having stratified functional properties – Part 2: Height characterization using the linear material ratio curve”
D. J. Whitehouse, Handbook of Surface Metrology, Institute of Physics Bristol, 1994.
Leigh Mummery, Surface Texture Analysis, The Handbook Hommelwerke GmbH, 1992 ( (203) 827-8500)
H. Dagnall M.A., Exploring Surface Texture, Rank Taylor Hobson Limited, Leicester, England, 1986 ( (800) 872-7265)
K. J. Stout, Development of Methods for the Characterisation of Roughness in Three Dimensions, 2000, Penton Press,
London, UK ISBN 1 8571 8023 2.