How to Use This Book

Every illustration in this book is a live model, computed on the page when you scroll to it, and you can handle it. This short chapter explains how, and then gives a first lesson in the most important skill the book tries to teach: how to look at a building.

Handling the figures

• Turn a model by dragging it. Zoom with the scroll wheel or a pinch; pan by dragging with the right mouse button or two fingers.
• Ink, Stone, Plan: the three buttons on each figure change how it is drawn. Ink imitates the engravings of the old treatises, shading surfaces with cross-hatching; Stone lights the model like a real building in sunlight; Plan shows it as a translucent blueprint so that you can see through walls to the structure behind.
• ⟷ shows or hides the labels and dimension lines. Dimensions of the classical orders are given in D, the lower diameter of the column; buildings are measured in metres.
• ↻ makes the model turn slowly by itself. ⌖ resets the view. ⤢ opens the figure full screen.
• Many figures have controls below them (buttons, menus and sliders). Each control is one of the rules in the text. Change it and the model is rebuilt.
• Explore ↗ opens the model in the Cabinet of Models, where all of its controls are available.

The three drawing styles apply to the whole book at once, and the page itself changes to match: choose Plan in the header and the book turns into a blueprint. Your choice is remembered.

Rules, styles and treatises

Rules are set in boxes marked ℟ (the old sign for recipe, “take this”). Each gives the rule in a sentence or two, often a formula, and the treatise and passage it comes from. Follow the title to the rule’s own page, where its figure appears large with all of its controls, together with related rules. The rule of intercolumniation is a good one to begin with.

℟The five intercolumniations

Columns may be spaced 1½ diameters apart (pycnostyle), 2 (systyle), 2¼ (eustyle), 3 (diastyle) or more (araeostyle). The eustyle, with a wider central bay of 3 diameters, is the best for use and beauty.

clear space = 1½ · 2 · 2¼ · 3 · >3 D

Words of the builder’s art are underlined with a dotted line, like entablature or volute. Hover over one (or tap it) to read its definition without leaving the page; the full glossary is under Glossary in the header. Press / at any time to search the whole book.

The Styles section arranges the traditions of the world on a timeline; each style has its own page with its characteristics, its buildings, its rules and its models. The Rules atlas lets you filter every rule in the book by subject, style or source. The Library holds the treatises: Vitruvius can be read there in full, with live figures set beside the passages they illustrate.

How to look at a building

Faced with an unfamiliar building, people often look for ornament first (a carved capital, a pointed window) and try to name a style. It is better to begin with the big questions and work down to the details. The following order of looking works for almost any building in the world.

1. How does it stand up? Find the structure. Is the weight carried by walls or by a frame of posts and beams? Are openings spanned by lintels or by arches? Are the roofs flat, pitched, vaulted or domed? The structure sets the limits within which everything else happens. (Part I of this book is about these choices.)
2. How is it arranged? Look for axes and symmetry. Where is the entrance, and where is the most important space? Is there a sequence (gate, court, hall, sanctuary) leading you inward? Is the plan centralised or longitudinal?
3. How is it divided? Read the façade from bottom to top and from side to side. Nearly every building has a base, a middle and a top, and nearly every façade is divided into bays: repeated vertical units marked by columns, pilasters, buttresses or windows. Count them: odd numbers give a central bay on the axis.
4. How is it proportioned? Compare heights with widths. Is the building squat or slender? Are the storeys equal, or does each become lighter as it rises? Are the openings tall or wide? Proportion is where the rules of each tradition are most precise.
5. How is it finished? Only now look closely at the details (the mouldings, capitals, tracery, brackets or glazing), which are the vocabulary of a style and usually the surest guide to its date.

This book follows the same order. It begins with structure and the elements of building, moves to proportion and the classical orders, and only then surveys the styles, each of which can be understood as a particular answer to the same questions.