Elevation changes should also be studied during the development of functional diagrams. It is during this stage that the designer should start thinking about the third dimension of the ground plane. The designer might ask: “Should one have to go up from the lawn area to the outside entertaining space, or should the two spaces be at the same elevation? If there is to be a change, about how much should it be? One foot? Three feet?”
One way elevational changes between spaces can be expressed in a diagram is by means of spot grades (Figure 8—31). This method allows the designer to determine what space is higher than another and by approximately how much. Another way of indicating elevation change in the functional diagram is by lines that represent step locations along a circulation path (Figure 8—32).
As can be seen from the preceding paragraphs, there are a number of factors of design organization that need to be thought about during the functional diagram phase. It is not always easy to study all these factors together, but it is essential to do so. It is necessary to examine each of these factors in association with the others so the overall design can function in a logical, well-planned, and coordinated manner. The more study given to the organization of a design at this time in the design process, the easier the design decisions become in subsequent phases.