Overview
EN ISO 25178-1:2016 - "Geometrical product specifications (GPS) - Surface texture: Areal - Part 1: Indication of surface texture" defines how to indicate areal (3D) surface texture requirements in technical product documentation. Published by CEN as the European adoption of ISO 25178-1:2016, this standard specifies the graphical symbols, composition rules and annotation practices used on drawings, specifications, contracts and reports to make areal surface texture requirements unambiguous.
Keywords: EN ISO 25178-1:2016, surface texture, areal, GPS, graphical symbols, technical product documentation.
Key topics
- Scope and purpose: Rules for indicating areal surface texture requirements by graphical symbols in technical documentation.
- Graphical symbols: Uses symbols similar to ISO 1302 with a distinguishing rhomb to identify areal surface texture; expanded symbols indicate whether material removal is permitted or not. An “all-around” modifier (circle) can mark integral features.
- Composition of complete symbols: Specifies positions for information items (e.g., parameter, tolerances, modifiers) so annotations are clear and consistent.
- Indication of parameters and tolerances: Rules for defining which areal surface texture parameters apply and how tolerances are shown to ensure measurable, enforceable requirements.
- Orientation and evaluation area: Guidance on evaluation-area orientation, intersection-plane indicators and coordinate-system declaration to avoid ambiguity.
- Digital product definition: Addresses use in digital CAD/PDM environments (see ISO 16792 compatibility).
- Normative annexes: Includes proportions/dimensions of symbols, examples for unambiguous specification, recommended procedures for intersection planes and relation to the GPS matrix model.
Relevant normative references include ISO 1101, ISO 1302, ISO 25178-2 and ISO 25178-3, ISO 14406 and ISO 16792.
Applications
- Engineering drawings and specifications where 3D surface texture matters (functional surfaces, sealing faces, optical components).
- Manufacturing and process planning to communicate whether material removal is permitted or required.
- Quality control, inspection planning and metrology reporting to specify which areal parameters and tolerances to measure.
- CAD/PDM and digital product-definition workflows that embed surface texture requirements in 3D models and technical data.
- Suppliers, OEMs and contract documents requiring consistent, unambiguous surface texture communication.
Who uses this standard
- Design and mechanical engineers
- Metrology and quality engineers
- Technical drafters and CAD specialists
- Manufacturing engineers and process planners
- Inspection labs and suppliers working to GPS (geometrical product specification) practices
Related standards
Using EN ISO 25178-1:2016 ensures consistent, machine-readable and legally defensible communication of areal surface texture requirements across design, manufacturing and inspection.