Smart line is a chain of connected line segments and/or arc segments. Smart line can be created by creating LineString or LinearComplex objects. The below code snippet shows how to create a smart line using LinearComplex and create alignment for that smart line.

Example

internal Alignment CreateAlignmentFromSmartLine()
        {
            //Create line to create complex line
            Bentley.GeometryNET.DPoint3d startPoint1 = new DPoint3d(707074.878, 231801.166, 0);
            Bentley.GeometryNET.DPoint3d endPoint1 = new DPoint3d(707505.580, 231599.077, 0);
            Bentley.CifNET.LinearGeometry.Line line1 = Line.Create1(startPoint1, endPoint1);

            //create arc to create complex line
            Bentley.GeometryNET.DPoint3d curveStartPoint = new DPoint3d(707505.580, 231599.077, 0);
            Bentley.GeometryNET.DPoint3d curveEndPoint = new DPoint3d(707527.726, 231597.626, 0);
            double radius = 30.48;
            Bentley.CifNET.LinearGeometry.Hand direction = Hand.CounterClockwise;
            Bentley.CifNET.LinearGeometry.CircularArc arc = Bentley.CifNET.LinearGeometry.CircularArc.
Create4(curveStartPoint, curveEndPoint, radius, direction);

            //Create line to create complex line
            Bentley.GeometryNET.DPoint3d startPoint2 = new DPoint3d(707527.726, 231597.626, 0);
            Bentley.GeometryNET.DPoint3d endPoint2 = new DPoint3d(707960.529, 231734.683, 0);
            Bentley.CifNET.LinearGeometry.Line line2 = Line.Create1(startPoint2, endPoint2);

            //add the lines and arc to list of LinearElements
            System.Collections.Generic.List<LinearElement> lines = new List<LinearElement>();
            lines.Add(line1);
            lines.Add(arc);
            lines.Add(line2);

            //create smart line of type linearComplex from LinearElements list
            Bentley.CifNET.LinearGeometry.LinearComplex smartLine = LinearComplex.Create1
(lines.ToArray(), false, false, 0.001);

            Bentley.CifNET.SDK.Edit.ConsensusConnectionEdit con = ConsensusConnectionEdit.GetActive();
            Bentley.CifNET.GeometryModel.SDK.GeometricModel gm = con.GetOrCreateGeometricModel();
            if (gm == null)
            {
                con.Close();
                con.Dispose();
                return null;
            }

            //begins mode to persist objects
            con.StartTransientMode();

            //create alignment from LinearComplex
            Bentley.CifNET.GeometryModel.SDK.Alignment al = gm.CreateAlignmentByLinearElement
(smartLine, true);

            //set feature definition
            string featureDef = "Alignment\\Geom_Baseline";
            if (featureDef != null && featureDef != string.Empty)
            {
                al.SetFeatureDefinition(featureDef);
            }

            //persist objects
            con.PersistTransients();

            return al;
        }

CreateAlignmentByLinearElement() of GeometricModel creates an alignment from a smart line of type LinearComplex created from 2 lines and one arc. SetFeatureDefinition() sets the feature definition to an alignment.