Element Relations

In the graphical presentation there are symbols showing how the elements relate to each other. Looking at the graph representing the Ship element, we can see that it may have an infinite number of child element but there must be at least 1. Each of the elements may be any of the child elements in the graph: "Defaults", "Seam", "ShellProfile", "ShellStiffener", "HullCurve", "PrincipalPlane or "Plane".

The symbol:

indicates "Choice", that means, you may select any of the child elements. The choice symbol can be combined with number restrictions, in this case the minimum number of choices is 1 and there is no upper limit. A single number like "3", indicates that there must be exactly three elements.

The "ShellProfile" graph illustrates another common relation, a "sequence":

This means that the "ShellProfile" element consists of all the listed child elements. They have to appear in the same order as in the graph. However, if the child element is drawn with a dashed line it is an optional element. In this example the "Material" element must be given in the input, while the "Position" and "Features" elements can left out. The ShellProfile element must have at least one "Branch" element but no more than 999.