.NET version of SampleElevations() was not included in AutoCAD Civil 3D 2012 release. However, in 2013 release, it's included : public Point3dCollection SampleElevations(ObjectId curveId);
It takes an ObjectId of Autodesk.AutoCAD.DatabaseServices.Curve and the curve can be a line, arc and so on. Here is a C# code snippet which demonstartes usage of this API function in AutoCAD Civil 3D 2013 :
public static void DemoSurfaceSampleElevations2013()
{
// Get the AutoCAD Editor
Editor ed = Application.DocumentManager.MdiActiveDocument.Editor;
//select a surface
PromptEntityOptions selSurface = new PromptEntityOptions("\nSelect a Tin Surface: ");
selSurface.SetRejectMessage("\nOnly Tin Surface is allowed");
selSurface.AddAllowedClass(typeof(TinSurface), true);
PromptEntityResult resSurface = ed.GetEntity(selSurface);
if (resSurface.Status != PromptStatus.OK) return;
ObjectId surfaceId = resSurface.ObjectId;
//select a polyline
PromptEntityOptions selPline = new PromptEntityOptions("\nSelect a polyline: ");
selPline.SetRejectMessage("\nOnly polylines allowed");
selPline.AddAllowedClass(typeof(Polyline), true);
PromptEntityResult resPline = ed.GetEntity(selPline);
if (resPline.Status != PromptStatus.OK) return;
ObjectId plineId = resPline.ObjectId;
Database db = Application.DocumentManager.MdiActiveDocument.Database;
using (Transaction trans = db.TransactionManager.StartTransaction())
{
TinSurface surface = trans.GetObject(surfaceId, OpenMode.ForRead) as TinSurface;
// SampleElevations(ObjectId curveId) returns a Point3dCollection
Point3dCollection intPts = new Point3dCollection();
intPts = surface.SampleElevations(plineId);
if (intPts.Count != 0)
{
foreach (Point3d pt in intPts)
{
ed.WriteMessage(string.Format("{0} {1}", Environment.NewLine, pt.ToString()));
}
}
trans.Commit();
}
}
