Drawing, Sketching and Trade-Related Technical Representation
This domain tests whether you can read and produce simple trade drawings - plans, elevations and sections of a room, colour-scheme elevations showing dado and skirting lines, and freehand sketches of mouldings and joints - using correct projection, scale, line types and dimensioning.
Projection and views
India follows first-angle projection: the object sits between observer and plane, so the view from the front appears below the plan. A plan is a horizontal cut seen from above; an elevation is a vertical face; a section cuts through to show construction. Hidden edges are dashed, visible outlines thick and continuous, centre lines chain dash-dot, dimension lines thin.
Scale and dimensioning
Common scales: 1:20 for details, 1:50 for room layouts, 1:100 for building plans. Dimensions are given in millimetres with the numeral above an unbroken dimension line between arrowheads and extension lines; units are stated once in the title block. Every drawing carries a title block with scale, date and sheet number.
Worked example
Draw a 4.2 × 3.0 m room at 1:50 with a 0.9 m dado. Reasoning: at 1:50, 1 m becomes 20 mm. So the plan is 84 mm × 60 mm, and the dado line on the elevation sits 18 mm above floor level, with a 100 mm skirting drawn 2 mm high. Mark the dado as a chain line and dimension it 900 mm.
Trade drawings you must produce
Colour-scheme elevation showing which product goes on wall, dado, skirting and ceiling; location sketch of a room with door and window symbols; freehand isometric of a moulding or bead.
Traps that cost marks
Mixing first- and third-angle layouts; forgetting the stated scale; omitting the unit or dimension arrows; drawing hidden edges as thick lines; no title block.