Overview
EN ISO 5456-1:1999 / ISO 5456-1:1996 - Technical drawings - Projection methods - Part 1: Synopsis provides a concise survey of the different projection methods used in technical drawing. It defines key terms and explains the geometric relationships and invariants that distinguish orthographic, axonometric and central (perspective) projection systems. This part is a high-level guide; detailed rules for each method are covered in Parts 2–4.
Key topics
- Survey of projection systems: categorizes projection methods by projector type (parallel or convergent), projection plane orientation (orthogonal or oblique) and object position relative to the projection plane.
- Definitions and terminology: clear definitions for terms such as pictorial representation, true view, exploded view and principal view, based on ISO vocabulary references.
- Geometrical orientation: coordinate axes (X, Y, Z) and coordinate planes (XY, YZ, XZ) using the right-hand rule; guidance ties to ISO 1503 for spatial orientation.
- Projection invariants: which geometric properties are preserved for each method, e.g. angle and similarity preservation for central projections, parallelism and divisional ratios for oblique and orthogonal projections.
- Tabular comparison: concise comparison (Table 1) of orthogonal, axonometric and central projection characteristics - view type (2D vs 3D), projection centre (finite vs infinite), and typical applications.
- Normative references: links projection method rules to other standards (ISO 10209, ISO 128, ISO 1503) for consistent technical documentation vocabulary and presentation.
Applications and users
EN ISO 5456-1 is intended for professionals who create, read or manage technical drawings and need a consistent understanding of projection choices:
- Mechanical, civil and architectural drafters and engineers
- CAD and technical illustrators producing pictorial or orthographic views
- Technical documentation authors (manuals, assembly instructions, exploded views)
- Quality, compliance and document control personnel who implement drawing standards
- Educators and students in engineering graphics and drafting courses
Practical value: helps teams choose the most appropriate projection method for clarity, manufacturability and communication (e.g., orthographic for precise dimensioning, pictorial/axonometric for easy visualisation, central projection for realistic representation).
Related standards
Keywords: technical drawings, projection methods, ISO 5456-1, orthographic projection, axonometric, central projection, pictorial representation, engineering drawings, CAD.