7 The nearest tenth of an inch

All these shaped details had the quality, like the cells of a plant, or of the human body, that they are created, shaped, according to context, according to need, in such a way as to enhance the larger whole. None are prefabricated.
This is technically essential for unfolding, though it was difficult to achieve in the late 20th-century world. But the technical difficulty does not make it any less necessary from the point of view of life in the fabric of the building. Its life depends on its variability, on its flexibility, on the degree to which it can be shaped, and adapted, while it is being made.
To understand the importance of “making” buildings in the technical sense I have defined, it is necessary to grasp fully how and to what extent the life of a living field of centers depends on getting small dimensions exactly right.

The shape of an arch drawn in pencil on a board may be exactly right — it has a beautiful feeling. A copy of the shape, made by someone else who does not understand the centers, even if his copy is accurate to within a half inch all along the line — often has no feeling left in it at all.

Tiny fractions of an inch have a large effect on the relative proportion of the parts and therefore define entirely different fields in the nearby space. Sometimes a center no more than a quarter of an inch across may support another center which is fifteen or twenty feet in diameter.
This is the typical case, not an exception. The same thing happens everywhere in a building. Every single line you draw has, in its microstructure, the potential to have a critical effect on the presence or absence of centers in the large. If we don’t get the proportions exactly right we don’t produce the centers and the whole thing falls apart.
No center is alone. The smallest centers therefore play a key role in the intensity of the largest ones.

It will not be possible to get life in a structure unless the actual method of making is capable of responding, step by step, to every subtle variation in the wholeness which exists. […]
It is therefore inherently impossible to make a successful building by a form of mass production or prefabrication which relies on identically repeated details with no possibility of modification. This is true because the necessary adaptations of shape and size in every detail cannot be made if the components are standardized. It cannot be done because the minute adaptations which are needed to get the field of centers just right at each point has to be “on its toes”. It has to be capable of responding to large changes and small changes, and these are not predictable.
The essential idea, then, is that every building part and every detail must have the capacity to form centers. That means, first the details must be of a type which is able to form a strong center; second, they should be made in a way that allows fine tuning so that once it is being built, it can be adjusted in size, shape, and character to make its existence as a center more deeply felt. Then the detail can come to life, and the larger centers made of these details may themselves be intensified.
It is only possible to do all this by means of a method of construction in which we gauge the wholeness which exists while the building is laid out, room by room, and then modify it gradually to get the living structure right in its microstructure, too.

#book/The Nature of Order/3 A Vision of a Living World/15 All Building as Making#