Flatten Feature Line

In Civil 3D there are several ways to flatten a feature line to 0 elevation. You may find that none of them are very convenient. It may be nice to have the ability to right click a feature line and flatten it. To do it now you have to go into the elevation editor or use the regular AutoCAD FLATTEN command. One can use the API to add a command to the right click menu to flatten a feature line from there. To do it modify the cui and add the command to the right click menu of a feature line. There is a way to programmatically add it, but I didn’t do it here.
The code to do it in vb.net is below:

   1:  Option Explicit On

   2:  

   3:  Imports System.Runtime.InteropServices.Marshal

   4:  Imports Autodesk.AutoCAD.Runtime

   5:  Imports Autodesk.AutoCAD.ApplicationServices

   6:  Imports Autodesk.AutoCAD.DatabaseServices

   7:  Imports Autodesk.AutoCAD.EditorInput

   8:  Imports Autodesk.AutoCAD.Geometry

   9:  Imports Autodesk.Civil.DatabaseServices.Styles

  10:  Imports Autodesk.Civil.ApplicationServices

  11:  Imports Autodesk.Civil.Land.DatabaseServices

  12:  Imports AeccLandLib = Autodesk.AECC.Interop.Land

  13:  Imports AeccLandUi = Autodesk.AECC.Interop.UiLand

  14:  Imports AcadCom = Autodesk.AutoCAD.Interop

  15:  Imports System.Security

  16:  Imports C3DRemindersPack.Utilities

  17:   

  18:  <Assembly: CommandClass(GetType(FlattenFeatureLine))> 

  19:   

  20:  Public Class FlattenFeatureLine

  21:   

  22:      Public Shared g_sName As String

  23:   

  24:      <CommandMethod("C3DRFlattenFeatureLine", CommandFlags.UsePickSet Or CommandFlags.Redraw Or CommandFlags.Modal)> _

  25:      Public Sub cmdFlattenFeatureLine()

  26:   

  27:          Try

  28:              'Get Civil 3D application, document and database

  29:              GetCivilObject()

  30:   

  31:              Dim oDoc As Document = Application.DocumentManager.MdiActiveDocument

  32:              Dim ed As Editor = oDoc.Editor

  33:   

  34:              Try

  35:                  Dim selectionRes As PromptSelectionResult = ed.SelectImplied()

  36:                  If selectionRes.Status = PromptStatus.Error Then

  37:                      ' Ask the user to select points.

  38:                      Dim selectionOpts As New PromptSelectionOptions()

  39:                      selectionOpts.MessageForAdding = vbLf & "Select feature line to flatten: "

  40:                      selectionRes = ed.GetSelection(selectionOpts)

  41:                  Else

  42:                      ' If there was a pickfirst set, clear it.

  43:                      ed.SetImpliedSelection(New ObjectId(-1) {})

  44:                  End If

  45:   

  46:                  ' If the user hasn't cancelled.

  47:                  If selectionRes.Status = PromptStatus.OK Then

  48:                      ' Take the objects one by one.

  49:                      Dim tr As Transaction = oDoc.TransactionManager.StartTransaction()

  50:                      Try

  51:   

  52:                          Dim objIds As ObjectId() = selectionRes.Value.GetObjectIds()

  53:                          For Each objId As ObjectId In objIds

  54:                              Dim ent As Entity = DirectCast(tr.GetObject(objId, OpenMode.ForRead), Entity)

  55:                              ' Check to see if the entity is a point.

  56:                              If TypeOf ent Is FeatureLine Then

  57:                                  Dim oFeatLine As AeccLandLib.AeccLandFeatureLine

  58:   

  59:                                  Dim entid As ObjectId = ent.ObjectId

  60:                                  Dim obj As Object = g_oCivil3DDoc.ObjectIdToObject(entid.OldIdPtr)

  61:                                  oFeatLine = obj

  62:                                  oFeatLine.ShowToolTip() = False

  63:                                  Dim dPoints() As Double

  64:                                  dPoints = oFeatLine.GetPoints()

  65:   

  66:                                  Dim i As Integer

  67:   

  68:                                  For i = 2 To UBound(dPoints)

  69:                                      dPoints(i) = 0

  70:                                      i = i + 2

  71:                                  Next

  72:   

  73:                                  oFeatLine.SetPointsElevation(dPoints)

  74:   

  75:                              End If

  76:                          Next

  77:                          tr.Commit()

  78:                      Catch ex As Autodesk.AutoCAD.Runtime.Exception

  79:                          ed.WriteMessage(ex.Message)

  80:                          tr.Abort()

  81:   

  82:                      End Try

  83:                  End If

  84:              Catch ex As Autodesk.AutoCAD.Runtime.Exception

  85:                  ed.WriteMessage(ex.Message)

  86:              End Try

  87:   

  88:   

  89:   

  90:          Catch ex As Exception

  91:   

  92:          Finally

  93:   

  94:   

  95:          End Try

  96:   

  97:   

  98:      End Sub

  99:   

 100:  End Class

I may have some unneeded items in it, but it should get the job done. Hopefully in a future version the Civil 3D developers will provide the command currently located on the Elevation Editor. I didn’t test it, but the code should take several selected feature lines and flatten all of them. You should be able to take the code from the Civil 3D Reminders Pack and add this class to it and compile the code and use netload to load the dll.