## Modeling by segments

The first step in defining the three-dimensional geometry of the elements in CADAM3D is a 2D sketch (the section). It is assumed that each section can be defined by an assemblage of simple geometric elements. Figure 10 shows the CADAM3D window used to define the 2D section of a chute. The segments used to create the sketch are numbered consecutively from upstream to downstream.

Figure 10

Four basic configurations can be used to define each segment shape: the line, the circular arc and two curves defined respectively by a power equation and a polynomial.