Standard vs Non Destructive Breaklines in Civil 3D 2015

by Graham Riddleston

Ever wondered what the difference is between a standard and a non-destructive breakline is? This should help.

Standard Breakline
A Standard breakline is a line used to define a distinct feature on a surface, for instance: bottom of bank, top of bank, centre of ditch, edge of carriageway etc. In a Civil 3D triangulated surface (TIN) a triangle is not permitted to cross a breakline, therefore triangle edges will be formed to follow any breakline.

Image 1: 3D Feature before it is added to the surface triangulation:

Image 2: 3D Feature added to the surface triangulation as a Standard Breakline.
Notice how the original triangulation has been altered:

Image 3: 3D Feature added to the surface triangulation as a Non Destructive Breakline.
In this case the original triangulation has been maintained but the breakline has added extra triangles. In other words it has only added triangles but not affected any of the existing triangles: