SQA National 5 Graphic Communication: a complete overview of 2D graphic communication

2D graphic communication is one of the two main strands of National 5 Graphic Communication. It is the technical, production-style side of the course: drawing products and buildings to British Standards so that anyone can read them and make the right thing. This guide maps each key area; each has its own answer page with worked examples and exam questions.

Orthographic drawing and third-angle projection

Orthographic drawing describes a product with flat, straight-on views. National 5 uses third-angle projection, where the plan sits directly above the front elevation and an end elevation sits on the side it was viewed from. The three views line up, so a feature can be traced between them: breadths match between the front elevation and plan, heights between the front elevation and end elevation. A projection symbol identifies the method.

British Standards line types and conventions

Each line on a drawing has a fixed appearance and meaning. A thick continuous line is a visible outline; a thin continuous line is for dimensions, projection and leader lines; a thin dashed line shows hidden detail; a thin chain line is a centre line; faint construction lines set the drawing out. These conventions are protocols, so every reader interprets the drawing the same way.

Dimensioning and tolerances

Dimensions are added with thin dimension lines (arrowheads), projection lines (with a small gap at the outline) and leader lines. Diameters carry the phi symbol and radii a capital R. A tolerance such as $25 \pm 0.1$ states the largest ($25.1$) and smallest ($24.9$) acceptable size, because no part is made exactly to size.

Sectional and assembly drawings

A sectional view cuts the object open along a cutting plane to show internal detail, with cut faces shown by 45-degree hatching; features such as shafts, bolts and ribs are left unhatched. An assembly drawing shows parts in their fitted positions with a parts list and item references (balloons), and an exploded version shows the order of assembly.

Building drawings, symbols and scale

Buildings are drawn as floor plans (one storey from above), site plans (the plot) and location plans (the surrounding area). Standard British Standards symbols show doors, windows and fittings, and a scale such as $1:50$ reduces every real length by the same ratio so a large building fits on a sheet in proportion.

How 2D graphic communication is examined

The question paper rewards precise recall of conventions and short, accurate working:

1. Read drawings. Identify views, line types, sections and building plans, and say what each shows.
2. Apply conventions. State the British Standards rules for projection, line types, dimensioning, hatching and symbols.
3. Calculate. Work out tolerance limits and scale lengths.
4. Explain. Say why conventions, sections, assemblies and scale are used.
5. Use the right words. Marks reward exact terms such as third-angle projection, hidden detail, cutting plane, parts list, site plan and tolerance.

How to study 2D graphic communication

This strand rewards learning a fixed set of conventions until they are automatic.

1. Learn the line types as pairs. Each line is a look plus a meaning; revise both together.
2. Drill projection placement. Practise placing the plan and end views in third-angle until it is instinctive.
3. Practise calculations. Tolerance limits and scale conversions are quick marks once rehearsed.
4. Memorise the standard symbols. Doors, windows and sanitary fittings recur on floor plans.
5. Use past papers. SQA past papers and marking instructions show the wording markers reward.

For the official course specification

The SQA publishes the full National 5 Graphic Communication course specification, specimen question paper and coursework task at sqa.org.uk. Always revise from the current specification and SQA past papers, because question style, conventions and terminology are board-specific.