Have you ever started laying out a pipe network using the cover and slope pipe rule or Pipe Cover and found the pipes down near the zero elevation? Well if your like me you don’t really appreciate having the pipes down at the zero elevation. Here’s a way to change the rule to put the elevation at a place which would be more desirable without having to move the pipes later on.

NOTE: Before you start make sure you save a copy of the C3DPipeRules.dvb to another location to easily go back to the original state.

To do this open up the Visual Basic Editor after you have worked with a pipe (working with a pipe should load the C3DPipeRules.dvb file automatically). This post has more information on how to load Visual Basic files. Go to the CoverAndSlope Module and scroll down to the Public Sub ApplyWithoutSurface routine, to the part that is below:

1 ‘ If the last elevation is equal to our double max,
2 ‘ then the last elevation has not been set in the network state
3 ‘ and we will set the starting elevation to the minimum cover
4 ‘
5 If dLastElevation = c_DBL_MAX Then
6 dNewPipeZ = 0
7 If eFlowDir = aeccPipeFlowDirectionStartToEnd Then
8 dNewPipeZ = dNewPipeZ – dMinimumCover
9 oPipe.StartPoint.Z = (dNewPipeZ – oPipe.OuterDiameterOrWidth * 0.5)
10
11 ElseIf eFlowDir = aeccPipeFlowDirectionEndToStart Then
12 dNewPipeZ = dNewPipeZ – dMinimumCover
13 oPipe.EndPoint.Z = (dNewPipeZ – oPipe.OuterDiameterOrWidth * 0.5)
14 End If
15 ‘ otherwise set the starting elevation to the last elevation
16 ‘
17 Else
18
19 If eFlowDir = aeccPipeFlowDirectionStartToEnd Then
20 oPipe.StartPoint.Z = dLastElevation
21 ElseIf eFlowDir = aeccPipeFlowDirectionEndToStart Then
22 oPipe.EndPoint.Z = dLastElevation
23 End If
24 End If

You can change the dNewPipeZ = 0 (Line 5), to a new value or we can change it to prompt the user for the elevation they want to use. The new line could be the following:

dNewPipeZ = ThisDrawing.Utility.GetReal(vbCrLf & “Surface not found, enter invert elevation to use:”)

If you then create a pipe network you will see that we have two problems with the change of prompting the user for the invert elevation. The first is the invert elevation of the first pipe is not the same as the one we entered into the program and the second is that it asks you again to enter the invert elevation at the end of laying out the network.

The first problem is explained in the code shown above, it is setting the starting elevation to the minimum cover as told in the programming notes. To correct this remove lines 8 and 13 from the code above and change the negative sign and the word outer in lines 9 & 14 to a positive and Inner. I suggest using a ‘ before the line to remove it and adding a note to explain why you did the change so you can easily go back at a future date and reverse the revision. The oPipe.Endpoint.Z and oPipe.StartPoint.Z refer to the center of the pipe.

The next change we have to make is to get the program to not ask you what the invert elevation is the second time. To accomplish this we are going to add an If Then statement around where it is setting the starting elevation. So right after line 5 add:

If oPipe.StartPoint.Z = 0 Then

After line 16 put End If. So the finished code should look something like this:

1: ‘ If the last elevation is equal to our double max,

2: ‘ then the last elevation has not been set in the network state

3: ‘ and we will set the starting elevation to the minimum cover

4: ‘ This portion was revised to allow the user to input the starting elevation instead of

5: ‘ setting the starting elevation to the minimum cover.

6: ‘

7: If dLastElevation = c_DBL_MAX Then

8: ‘ To get the program to not ask us for the elevation again we will check to see if the start point z is zero

9: If oPipe.StartPoint.Z = 0 Then

10: dNewPipeZ = ThisDrawing.Utility.GetReal(vbCrLf & “Surface not found, enter invert elevation to use:”)

11:

12: If eFlowDir = aeccPipeFlowDirectionStartToEnd Then

13: ‘ Line below removed to allow the user to provide the invert elevation.

14: ‘ dNewPipeZ = dNewPipeZ + dMinimumCover

15: ‘ The + was a negative sign and Inner was Outer to get invert of the pipe instead of the top of pipe.

16: oPipe.StartPoint.Z = (dNewPipeZ + oPipe.InnerDiameterOrWidth * 0.5)

17:

18: ElseIf eFlowDir = aeccPipeFlowDirectionEndToStart Then

19: ‘ Line below removed to allow the user to provide the invert elevation.

20: ‘ dNewPipeZ = dNewPipeZ + dMinimumCover

21: ‘ The + was a negative sign and Inner was Outer to get invert of the pipe instead of the top of pipe.

22: oPipe.EndPoint.Z = (dNewPipeZ + oPipe.InnerDiameterOrWidth * 0.5)

23:

24: End If

25: End If

26:

27:

28: ‘ otherwise set the starting elevation to the last elevation

29: ‘

30: Else

31:

32: If eFlowDir = aeccPipeFlowDirectionStartToEnd Then

33: oPipe.StartPoint.Z = dLastElevation

34: ElseIf eFlowDir = aeccPipeFlowDirectionEndToStart Then

35: oPipe.EndPoint.Z = dLastElevation

36: End If

37:

38: End If

If you want to go back to the old way just copy over the changed C3DPipeRules.dvb and it should be back to the original state. You can download a hacked version here if you’d like to review.