Building Drawing
This domain tests drawing conventions - scales, line types, projection method, dimensioning, symbols and title block content - rather than site interpretation.
Scales
Site or block plan 1:1000 or 1:500; floor plan 1:100; sections and elevations 1:50; details 1:20 or 1:10.
Line types and projection
Continuous thick line = visible outline; dashed = hidden; chain or dash-dot = centre lines and grids; thin continuous = dimension and extension lines. India follows first-angle projection: the plan sits below the elevation and the left view sits on the right; the truncated-cone symbol identifies the method on the sheet.
What a sheet carries
Title block (project, client, drawing title, number, scale, date, revision), north arrow, grid lines, setting-out dimensions, room names and areas, level marks (GL, SSL, FFL), door and window marks, section marks, notes and legend.
Dimensioning rules
Dimensions in millimetres unless stated otherwise; dimension lines outside the view, figures readable from the bottom or right; overall and sub-dimensions both shown; no duplicated dimensions; setting-out tied to the structural grid.
Worked example
On a 1:50 drawing a wall measures 84 mm between faces. Reasoning: 84 × 50 = 4200 mm = 4.20 m. If the sheet was reduced from A1 to A4 for printing, the printed measurement is meaningless - always read the written dimension, not the scaled length.
Traps
Scaling from a photocopy; assuming third-angle projection; ignoring revision clouds; treating an elevation as a section; omitting the level marks that the site needs for setting out.