A breakline is a feature line or polyline representing a ridge or some other feature that the user wishes to preserve in a mesh made up of triangular elements. In other words, a breakline is a series of edges to which the triangles should conform to, i.e., not intersect.

Breaklines (a) Triangulated Mesh and Breakline. (b) Triangulated Mesh After the Breakline has been Processed.

Add Breaklines

Breaklines can be processed using the Add Breaklines command from the Mesh menu. Before selecting the command, one or more sequences of nodes defining the breakline(s) should be selected using the Select Node Strings tool in the Tool Palette.

As each breakline is processed, the triangles intersected by the breakline are modified by adding new nodes at necessary locations to ensure that the edges of the triangles will conform to the breakline. The elevations of the new nodes are based on a linear interpolation of the breakline segments. The locations of the new nodes are determined in such a way that the Delauney criterion is satisfied.

Related Links:
Editing 2D Meshes