A profile is defined by a profile name, an optional description and a 2-dimensional pointlist with both coordinates mandatory. All point coordinates are transferred to the global coordinate system depending on the context they are used in. The points have to be ordered in a mathematical positive sense. The x-coordinates of the profile has to be normalized between 0 and 1. First and last point may, but need not to, be identical. Hence, it is possible to include "open" profiles. However, the trailing edge position of the upper and lower point need to be identical. No crooked trailing edges are possible.

Example 1: For a conventional nacelle profile, the airfoil coordinates are defined in x and y. The points have to be ordered from the trailing edge along the lower side to the leading edge and then along the upper side back to the trailing edge. When used for a nacelle the profile axis align with the global axes as follows: +x_profile -> +x_global; +y-profile -> -z_global

Example 2: For a fuselage, the coordinates are also given in x and z with x as the normalized fuselage height. Starting point of the profile should be the lowest point (typically in the symmetry plane), then upwards on the positive x-side up to the highest point (again, typically in the symmetry plane). Depending on, whether the fuselage shall be specified with symmetry condition or not, the profile either ends there, or continues on the negative x-side back down to the lowest point.

Alternatively, it is possible to specify the coordinates of a profile via the CST (class function /shape function transformation technique) notation. Please see the cst2DType for further information.

A profile can be symmetric. In that case the profile is interpreted as being not closed and will be closed by mirroring it on the symmetry plane.

Reference