Architectural Design

The design process: brief and data

A building starts with a brief: a short list of what the people need (rooms, activities), the site (size, slope, sun, wind, road), the budget and the rules of the town. The designer collects this data first.

Then the steps are: sketch ideas by hand, choose the best, draw plans, elevations and sections, build a model, correct mistakes, and finally prepare the final drawings that builders will use. Design is a loop: draw, check, improve.

Projective methods: plan, elevation, section, perspective

We draw a 3D building on flat paper in several ways.

• Plan: a view from the top, as if the roof is cut off at about 1 m above the floor. It shows walls, doors and room names.
• Elevation: a front or side view. It shows height, windows and the roof.
• Section: a view as if the building is cut by a knife. It shows floors, stairs and the heights inside.
• Axonometric / isometric: one drawing that shows three faces with true measures along the axes.
• Perspective: how the eye sees. Lines going away meet at a vanishing point, so far things look smaller.

Theory of shadows: if the sun's rays come at an angle, a vertical wall of height h casts a shadow of length h ÷ tan(angle). A low sun gives a long shadow; a high sun gives a short one. Drawings show shadows to make the building look solid.

Function, structure and statics

Function means that the building must work: the kitchen near the dining room, a bedroom away from the street noise, a clear path to the exit.

Structure means how the building stands up. Loads (weight of people, furniture, the building itself) travel from the roof to the slab, to the walls or columns, then to the foundation and the ground. This is called statics: forces balance, so nothing moves. A beam bends, a column is squeezed. Long spans need deeper beams.

Good design joins both: a room that works and a structure that is safe and simple.

Modularity, symmetry, proportion and typology

A module is a basic repeating measure, such as 1 m, or a 3 m by 3 m bay. When doors, windows and rooms follow a module, building is faster and cheaper, and the look is tidy.

Symmetry means one side mirrors the other. Proportion means a pleasing ratio between parts, for example a window taller than it is wide, or the ratio 1 : 2 for a room.

Typology means groups of buildings with a similar plan: a courtyard house, a row house, a tower block, a school with corridors. Distribution is how people move inside: halls, corridors, stairs and lifts.

CAD, models and sustainability

CAD (computer-aided design) draws in 2D and builds 3D models that you can rotate and cut. It makes changes fast. Physical models in card or foam let you hold the idea; virtual models let you walk through it on a screen.

Sustainability: use less energy and water, choose local and recyclable materials, plan shade and cross-ventilation, and keep the building useful for many years. Ethics: the building must be safe, accessible for all (ramps for wheelchairs), and fair to neighbours and nature.

Try it: design a classroom corner

Draw a rectangle 8 squares by 6 squares on graph paper (1 square = 1 m). Place four rooms. Then in the 3D, set the sun to a low angle and note the shadow length; do it again with a high sun. Which is better for a hot afternoon?

Key formulas and definitions

• Shadow length = height ÷ tan(sun angle)
• Plan = top view; Elevation = front/side view; Section = cut view
• Module: repeat one measure (e.g. 1 m) for all parts
• Load path: roof → slab → wall/column → foundation → ground

Worked examples

Common mistakes

• Mixing up plan and elevation. Plan is from the top; elevation is from the front.
• Starting to draw before knowing the brief and the site.
• Making a design that looks nice but has no load path to the ground.
• Forgetting that a lower sun gives a longer shadow.