A boundary is a closed
polygon that affects the visibility of the triangles inside it.
When you create boundaries,
you specify whether they use arc tessellation and non-destructive breaklines.
AutoCAD Civil 3D supports the
following types of boundaries:
Displays all triangles inside the boundary; you can use it to create
visible areas within hide boundaries.
NoteThe effect of adding
multiple boundaries to a surface is dependent on the order in which
they are added. The effects of a boundary can be wholly or partially
overridden by a subsequent boundary.
- Data Clip.
Creates a surface boundary limited by a polygon object from the
drawing, such as 2D and 3D polylines, feature lines, survey figures,
parcels, and circles.
You can add more than one data clip boundary
to a surface. When you add data, only the most recent data clip
boundary is affected. A data clip boundary does not affect the visible
part of the surface, but acts as a filter on all data, such as points
and breaklines added to the surface after the creation of data clip.
For example, if you add a breakline to a surface following the creation
of a data clip boundary, only the part of the breakline that is
inside the data clip boundary is added.
Surface boundaries are
defined by selecting existing polygons from the drawing. The surface
definition displays the numerical ID and a list of vertices for