Engineering Graphics and Design Communication
What this domain tests
Engineering Graphics and Design Communication examines whether you can interpret and produce a correct technical drawing set: orthographic views, line conventions, dimensioning, sectioning, scales and title-block information. Marks are lost for convention errors, not for untidy lettering.
Core rules
- First-angle projection is the default in most South Asian and British-influenced practice: the object lies between the observer and the plane, so the top view is placed below the front view and the left-side view is placed on the right.
- Line hierarchy: continuous thick for visible edges, short-dashed for hidden edges, long-chain thin for centre lines and pitch circles, continuous thin for dimension and extension lines.
- Dimension once, on the view that shows the feature most clearly; give diameters with Ø, radii with R, and never dimension a hidden line if a visible view can carry the size.
- Sections use hatching at 45° with uniform spacing; adjacent parts get opposite or different hatch angles.
- Drawings conform to BS 8888/ISO 129 conventions, with general tolerances such as ISO 2768 unless the title block states otherwise.
Worked example
A 120 mm shaft is drawn at 1:5. The drawn length is 120/5 = 24 mm, but the dimension text must read 120, because dimensions state true size, not scaled size. A Ø20 mm cross-hole is shown as a circle in the end view; it is dimensioned Ø20 there once, not repeated as 20 in the longitudinal view.
Traps
Using third-angle placement; dimensioning to hidden lines; writing the scaled value; omitting centre lines on holes; crossing extension lines; forgetting units or the projection symbol.