(a) TIN and Breakline. (b) TIN After the Breakline has been Processed.
A breakline is a line representing a ridge or some other feature that the user wishes to preserve in a TIN. In other words, a breakline is a series of edges that the triangles should conform to, i.e., not intersect as shown below:
(a) TIN and Breakline. (b) TIN After the Breakline has been Processed.
Breaklines can be created using the Add Breaklines command from the TINs menu. Before selecting the command, one or more sequences of vertices defining the breakline(s) should be selected using the Select Vertex Strings tool in the Tool Palette.
Breakline options can be specified using the TINs | Settings menu command. When the Add supplementary points option is selected, new vertices are added to the TIN at necessary locations to ensure that the edges of the triangles conform to the breakline. The elevations of the new vertices are based on a linear interpolation of the breakline segments. The locations of the new vertices are determined in such a way that the Delauney criterion is satisfied. When the Swap edges option is selected, no new vertices are added to the TIN. The edges that intersect the breakline are swapped with the breakline to form triangles. The Delauney criterion is not maintained.
Related Links:
Editing TINs