Overview
EN ISO 5456-3:1999 (ISO 5456-3:1996) specifies rules for axonometric representations in technical drawings. It is part of the ISO 5456 series on projection methods and provides standardized conventions for producing parallel (axonometric) pictorial views used across mechanical, electrical, construction and other technical fields. The standard describes recommended axonometries, basic presentation rules, and references related drafting standards.
Key topics and technical requirements
- Recommended axonometries: isometric, dimetric and oblique (including cavalier, cabinet and planometric) axonometric types are defined and illustrated.
- Isometric: projection plane forms equal angles with X, Y and Z axes; projected unit lengths on X′, Y′, Z′ are equal (approx. 0.816 of real unit); common for showing three faces equally.
- Dimetric: two axes share the same scale, third differs (example ratio ux′:uy′:uz′ = 1/2 : 1 : 1), used when one view is of primary importance.
- Oblique: projection plane parallel to one coordinate plane; includes:
- Cavalier: third axis at 45° to plane, equal scale on all axes (simple to draw, but distorts depth).
- Cabinet: like cavalier but third axis scale reduced by 1/2 (better visual proportion).
- Planometric: projection plane parallel to horizontal plane; normal and shortened variants with scale ratios (1:1:1 or 1:1:2/3).
- Coordinate and object placement:
- Z-axis conventionally vertical.
- Objects oriented so principal faces, axes and edges are parallel to coordinate planes.
- Coordinate axes labeled with uppercase (X,Y,Z); use lowercase (x,y,z) when differentiating from other items.
- Presentation rules:
- Follow general presentation standards (ISO 128) for line styles, lettering (ISO 3098-1) and dimensioning (ISO 129).
- Hidden contours/edges preferably omitted.
- Hatching for sections: usually 45° relative to axes/contours; planes parallel to coordinate planes hatched parallel to projected coordinate axis (see ISO 6412-2).
- Dimensioning axonometric views is normally avoided; if used, apply the same rules as orthographic projections.
Applications and users
- Useful for creating clear pictorial views in:
- Technical manuals, assembly instructions and product illustrations
- CAD drafting and technical illustration where parallel projection is required
- Architectural and town-planning sketches (particularly planometric)
- Pipeline isometric references (see bibliography)
- Typical users: drafters, CAD operators, mechanical/architectural engineers, technical illustrators, standards/compliance officers.
Related standards
Keywords: axonometric representations, technical drawings, projection methods, isometric, dimetric, cavalier, cabinet, planometric, EN ISO 5456-3, ISO 5456-3.
