The following sample code demonstrates how to divide a selected curve object by a specified number of segments.

C++

  CRhinoCommand::result CCommandTest::RunCommand(const CRhinoCommandContext& context)
  {
    CRhinoGetObject go;
    go.SetCommandPrompt( L"Select curve to divide" );
    go.SetGeometryFilter( CRhinoGetObject::curve_object );
    go.GetObjects( 1, 1 );


    if( go.Result() == CRhinoGet::cancel )
      return CRhinoCommand::cancel;


    if( go.Result() != CRhinoGet::object || go.ObjectCount() <= 0 )
      return CRhinoCommand::failure;


    CRhinoObjRef& objref = go.Object(0);
    const ON_Curve* crv = objref.Curve();
    if( !crv )
      return CRhinoCommand::failure;


    CRhinoGetInteger gi;
    gi.SetCommandPrompt( L"Number of segments" );
    gi.SetDefaultInteger( 2 );
    gi.SetLowerLimit( 2 );
    gi.SetUpperLimit( 100 );
    gi.GetInteger();


    if( gi.Result() == CRhinoGet::cancel )
      return CRhinoCommand::cancel;


    if( gi.Result() != CRhinoGet::number )
      return CRhinoCommand::failure;


    int count = gi.Number();
    count++;
    ON_SimpleArray<double> t( count );
    t.SetCount( count );


    int i;
    for( i = 0; i < count; i++ )
    {
      double param = (double)i / ((double)count-1);
      t[i] = param;
    }
    if( crv->GetNormalizedArcLengthPoints(count, (double*)&t[0], (double*)&t[0]) )
    {
      for( i = 0; i < count; i++ )
      {
        ON_3dPoint pt = crv->PointAt( t[i] );
        context.m_doc.AddPointObject( pt );
      }
      context.m_doc.Redraw();
    }
    return CRhinoCommand::success;
  }

VB.NET (Rhino 4)

  Public Overrides Function RunCommand(ByVal context As IRhinoCommandContext) _
    As IRhinoCommand.result


    Dim go As New MRhinoGetObject()
    go.SetCommandPrompt("Select curve to divide")
    go.SetGeometryFilter(IRhinoGetObject.GEOMETRY_TYPE_FILTER.curve_object)
    go.GetObjects(1, 1)


    If (go.GetResult() = IRhinoGet.result.cancel) Then
      Return IRhinoCommand.result.cancel
    End If
    If (go.GetResult() <> IRhinoGet.result.object Or go.ObjectCount() <= 0) Then
      Return IRhinoCommand.result.failure
    End If


    Dim objref As MRhinoObjRef = go.Object(0)
    Dim crv As IOnCurve = objref.Curve()
    If (crv Is Nothing) Then Return IRhinoCommand.result.failure


    Dim gi As New MRhinoGetInteger()
    gi.SetCommandPrompt("Number of segments")
    gi.SetDefaultInteger(2)
    gi.SetLowerLimit(2)
    gi.SetUpperLimit(100)
    gi.GetInteger()
    If (gi.GetResult() = IRhinoGet.result.cancel) Then
      Return IRhinoCommand.result.cancel
    End If
    If (gi.GetResult() <> IRhinoGet.result.number) Then
      Return IRhinoCommand.result.failure
    End If


    Dim count As Integer = gi.Number()
    Dim t(count) As Double
    For i As Integer = 0 To count
      t(i) = i / count
    Next


    If (crv.GetNormalizedArcLengthPoints(t, t)) Then
      For i As Integer = 0 To count
        Dim pt As On3dPoint = crv.PointAt(t(i))
        context.m_doc.AddPointObject(pt)
      Next
      context.m_doc.Redraw()
    End If
    Return IRhinoCommand.result.success
  End Function

C# (Rhino 4)

  public override IRhinoCommand.result RunCommand(IRhinoCommandContext context)
  {
    MRhinoGetObject go = new MRhinoGetObject();
    go.SetCommandPrompt("Select curve to divide");
    go.SetGeometryFilter(IRhinoGetObject.GEOMETRY_TYPE_FILTER.curve_object);
    go.GetObjects(1, 1);


    if(go.GetResult() == IRhinoGet.result.cancel)
      return IRhinoCommand.result.cancel;


    if(go.GetResult() != IRhinoGet.result.@object || go.ObjectCount() <= 0)
      return IRhinoCommand.result.failure;


    MRhinoObjRef objref = go.Object(0);
    IOnCurve crv = objref.Curve();
    if(crv == null)
      return IRhinoCommand.result.failure;


    MRhinoGetInteger gi = new MRhinoGetInteger();
    gi.SetCommandPrompt("Number of segments");
    gi.SetDefaultInteger(2);
    gi.SetLowerLimit(2);
    gi.SetUpperLimit(100);
    gi.GetInteger();
    if(gi.GetResult() == IRhinoGet.result.cancel)
      return IRhinoCommand.result.cancel;
    if(gi.GetResult() != IRhinoGet.result.number)
      return IRhinoCommand.result.failure;


    int count = gi.Number();
    double[] t = new double[count];
    for( int i=0; i<count; i++ )
      t[i] = (double)i / (double)count;


    if(crv.GetNormalizedArcLengthPoints(t, ref t))
    {
      for( int i=0; i<count; i++ )
      {
        On3dPoint pt = crv.PointAt(t[i]);
        context.m_doc.AddPointObject(pt);
      }
      context.m_doc.Redraw();
    }
    return IRhinoCommand.result.success;
  }