An airbag is composed of pieces of fabric sewn together. Taken separately, those pieces of fabric may be considered flat. Thus, to be able to describe their outline is sufficient for knowing their shape.

This is the definition that has been adopted in the folder: every piece of fabric (an airbag component) is defined by its outline; which, in turn is defined by a set of straight lines.

In practice, the starting point for the folder is 1D parts in HyperCrash (trusses, beams, springs). This will be discussed further in following sections.

Also, keep in mind that the folding process introduces new points into the initial geometry definition and that the meshing takes place at the end of the folding process. The job of the mesher is easier when it has some freedom in placing the mesh nodes. If the geometry is "rich" at the beginning, it may become "very rich" after the folding is done. The mesher's job may be difficult in this case. So when choosing the initial geometry, define only the necessary nodes so that the geometry definition might remain as light as possible.

Following, it is explained further that lines are used to define folds. Those lines will be used to cut and transform the airbag geometry. In order to keep the geometry as light as possible, it is better to use existing nodes for the lines' definition (thus, fewer new points are created) than to define them by entering the nodes' coordinates.

See also

Folder Overview

Batch Language

A Few Notions of Geometry