\inter_cut

Description 

As its name indicates this operator is a short-cut of two other ones:

• \intersection (cf. § page )
• \cut(cf. § page )

Geometrical operator, \inter_cut returns the intersection vertex of two edges given in parameter. Its second effect is to break the first edge parameter at the intersection point. So after the application of \inter_cut a new point is added to vertex data base (returned vertex), first parameter is modified and a new edge is created as the second part of the original broken edge.

Operator \inter_cut is useful to prepare elements before moving points (application of a real fold). All edges intersecting the fold line should be cut to make move.
This operator should only appear within a step block.

Figure: Example of operator \inter_cut. Edge [ab1, cd1] no longer exists and edges [ab1, o1] and [o1, cd1] are created.

Usage

\step {
  \square(a, b, c, d);
  ab1 = \fraction(a, b, 30, 100);
  cd1 = \perpendicular([c, d], ab1);
  \fold(ab1, cd1);
  da2 = \middle(d, a);
  cd2 = \middle(c, d);
  \valley_fold(da2, cd2);
  o1 = \inter_cut([ab1, cd1], [da2, cd2]); 
}

Formal structure

  RETURN_VERTEX = \inter_cut(EDGE_1, EDGE_2);

Parameters

  EDGE_1
  Description    : Indicates the first segment.
  Type           : Edge, vertex identifier pair.
  Allowed values : Any vertex identifier pair previously defined.

  EDGE_2
  Description    : Indicates the second segment.
  Type           : Edge, vertex identifier pair.
  Allowed values : Any vertex identifier pair previously defined.

Return value

  RETURN_VERTEX
  Description    : New vertex intersection of both segments
  Type           : Symbol, vertex identifier
  Allowed values : Any vertex identifier not already defined

Conditions

• Edges should not be parallel.