Define Platform Edge
First, identify the CAD elements that make up a Platform edge. The simplest Platforms are straight, needing only selection of a single line segment. Polylines may also be used, to represent curved platforms. Since selected CAD defines the edge alone, rather than the whole Platform, selected CAD may not be closed, overall (i.e., form a rectangle, square, pentagon, or other polygon). Selected CAD must not completely overlap either since this effectively creates a section of closed CAD. Selected CAD is checked and if it does not form a continuous line, an Error is raised, and the user must reselect.
Once a valid CAD selection has been made, there is a prompt to simplify the Platform edge, from which superfluous elements may be removed: