No matter which method you use to add breaklines to a surface’s definition, you will need to configure the type of breakline that it is. The breakline types are as follows:- Standard
- Standard breaklines can be 2D or 3D polylines, arcs, lines, splines, feature lines, figures, or parcels. These entities have the actual elevations for the surface assigned at their vertices. The vertex elevations become surface points, TIN lines are drawn along the breakline, and then the remaining triangulation is calculated. Standard breaklines represent both the horizontal and vertical locations of linear features of a surface.
- Proximity
- Proximity breaklines represent horizontal location only. In fact, if the entity used to define the proximity breakline is 3D, the vertex elevation will be ignored. The elevation of each vertex is determined from a nearby surface point already added to the surface.
- Wall
- Wall breaklines can be used to define near-vertical drops such as retaining walls or curb lines. You would define a wall breakline much the same as you would define a standard breakline. After selecting the feature, you would define a horizontal offset side and then an elevation difference at each vertex or for the entire length of the feature.
- From File
- The From File option is needed only if you have an FLT text file containing breakline data. This file type is usually the result of output from another program and contains XYZ data on each vertex for the lines described in the file. Once the FLT file has been imported, the effect on the surface is identical to a standard breakline. File Link options can be dynamically linked to the file, or the link can be broken so the surface will no longer be dependent on the file.
- Non-destructive
- Non-destructive breaklines neither change elevation nor change grades of the surface model. Non-destructive breaklines simply control the horizontal orientation of triangle lines. You may find yourself needing a non-destructive breakline in anticipation of cleaning up triangle data, as discussed later in this blog, in the section “Manual Surface Edits”.
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