Feature lines are 3D objects which can be used as grading footprints, surface breaklines and as corridor baselines.
For example, a feature line may represent an object in the drawing from which you want to grade, such as a swale or a ridge line. When you create a grading, you can select the feature line as the grading footprint.
You can draw feature lines, convert feature lines from existing objects and extract feature lines from alignments or corridors.
When you create new feature lines, or convert feature lines from existing objects, you can specify whether the feature lines are created at absolute levels, or whether they obtain their levels from a grading group or from a specified surface. Feature lines that are based on surface elevations can be relative to that surface, so they are updated when the surfaces changes.
You can draw straight and curved feature line segments. Unlike 3D polylines, feature lines support arcs without tessellation. Tessellation is undesirable in a grading footprint because it results in many small grading faces joined by radial corners. To avoid tessellation, you can create a feature line from a 2D polyline with arcs, and then apply levels using theGrading Level Editor. If you want to create a grading from a footprint that has tessellated curves, you can use the Fit Curve command to convert the tessellation to true arcs.