Graphic communication, sketching and design project representation
The final block asks for freehand drawing and for the graphic organization of a design proposal: a croquis acotado, a sketch of an object, or the set of views and perspectives that communicate a project. What is assessed is proportion, line hierarchy, correct standardization and whether the drawing communicates without the author present.
Core rules
- Croquización: start from the overall bounding box and the main axes, verify proportions, then subdivide. A croquis is freehand but proportional and must be dimensioned to be usable.
- Line hierarchy (UNE-EN ISO 128): thick continuous for visible outlines (about 0.5 mm), thin continuous for dimension lines, axes, hatching and construction lines (0.25–0.35 mm); dashed for hidden edges; dash-dot for axes of symmetry.
- Lettering (UNE-EN ISO 3098): upright or slanted capitals, height about 1/10 of the drawing's dominant line module, never handwritten cursive on a technical sheet.
- Sheet layout: title block, scale, north arrow on plans, view names, detail call-outs, and a graphic scale so the drawing survives photocopying.
- Project representation: plantas, alzados and secciones for the technical information; axonometrías, exploded views and perspectives for presentation; planos de taller (dimensioned, toleranced) versus planos de presentación (clean, uncluttered, colour allowed).
- Digital production: CAD for exact 2D/3D geometry and BIM for coordinated models; sketches remain the tool for the first design decisions and for recording on site.
Worked example
Sketch a bench 1800 × 450 × 450 mm on A3 (297 × 420 mm) at 1:20. The front elevation becomes 90 × 22.5 mm and the plan 90 × 22.5 mm, so both fit with room for dimensions and the title block (leaving 20 mm margins). Set the ground line first, place the elevation above the plan (first angle), draw the seat thickness with a thick line and the dimension lines thin. If a detail is needed, add a 1:5 detail of the joint rather than enlarging the whole sheet.
Traps that cost marks
Shading or colouring before proportions are verified; construction lines drawn as thick as outlines; using a non-normalized scale such as 1:7; omitting scale and title block; mixing millimetres and centimetres on the same sheet; presenting a design sheet without a single dimensioned view; drawing a croquis with a ruler and losing the freehand expressive quality the exercise asks for.