Adding boundaries to Civil 3D Surface object using .NET API

By Partha Sarkar

We can add boundaries to Civil 3D Surface object using the SurfaceDefinitionBoundaries class; this class encapsulates the boundary operation list for a surface. Note that, operations are stored in the order they are performed on the surface. SurfaceDefinitionBoundaries class has overloaded function AddBoundaries(). In the following example we will see how to add boundaries to a surface from a collection of entity ObjectIds using SurfaceOperationAddBoundary AddBoundaries(ObjectIdCollection boundaryEntities , double midOrdinateDistance, SurfaceBoundaryType boundaryType, bool useNonDestructiveBreakline ) 

There are few important notes on this API mentioned in Civil 3D .NET API Reference document which I am highlighting below - 

1. The parameter useNonDestructiveBreakline is ignored for a GridVolumeSurface or TinSurface with a DataClip boundary type.
2. When creating the DataClip/Outer boundary, the first ObjectId in boundaryEntities is used, and any other ObjectIds in the collection are ignored.
3. The first boundary in the boundaryEntities should be closed when creating a DataClip boundary.

 

And here is a C# .NET code snippet on usage of this API - 

 

try

{

  TinSurface surface = trans.GetObject(surfaceId, OpenMode.ForWrite) as TinSurface;

 

  // Add the selected polyline's ObjectId to a collection

  ObjectIdCollection boundaryEntities = new ObjectIdCollection();

  boundaryEntities.Add(plineId);

 

  // Access the BoundariesDefinition object from the surface object

  SurfaceDefinitionBoundaries surfaceBoundaries = surface.BoundariesDefinition;

 

  // now add the boundary to the surface

  surfaceBoundaries.AddBoundaries(boundaryEntities, 1.0, SurfaceBoundaryType.Outer, true);

 

  trans.Commit();

}

 

Hope this is useful to you!