Wires are set of Curves, used to create Sides. Wires can be open, close, and even have several lines that do not connect. However, some operations as meshing can only be applied to specific wires.

A wire orientation is given by the succession of its lines (see figure below). This orientation is relevant to define contact matrices, since the matter of the die must be on the right hand side when following the curve along its orientation. It is also relevant when meshing a face, since the wire must be defined “area to the left”. If the wire is made of only one curve, the orientation of the wire is taken as the one of the curve. If the wire is made of two curves, the first curve defines the wire orientation.

The wire can be defined with all its curves, but it is always possible to add more curves with the push function:

wire = wirset.add( Wire(number, [curve1, curve2, curve3, ...]) )
wire.push(curve4)
wire.push([curve5, curve6,...])

• Wire can be replaced by MultiProjWire (derived class). MultiProjWire can handle multiple projections when the normal is not continuous.
• For rigid-defo contact, a wire must be defined “area to the left, and the wire orientation if defined by the succession of its curves. * The function wire.reverse() inverts the order of definition of the wire, which also inverts the orientation of its normal. * To understand of Metafor calculates a wire average normal, which is useful in 3D contact, read Surfaces''.