From the point of view of structural function and the need to put the form together, the designer's choices must embrace not only its geometrical configuration but also all the details of its construction and of the manner in which it is to be put together -though they will often, in practice, be made by more than one person for all but the simplest forms. Apart from the overriding constraints imposed by the need to make the form stand, they will obviously be constrained also by the availability of materials and other resources and even by the time within which construction must be completed. These constraints operate in different ways, though, and are more restrictive or less so, according to the skill of the designer and the magnitude of the task. The greater this skill in relation to the demands made on it by the magnitude of the task and by the limited availability of materials and other resources, the greater the real freedom of choice. Moreover this freedom can usually be exercised in choosing the basic geometrical configuration, in detailing it, in deciding how to put it together, or in any combination of these.