Trimble Business Center

 View Only
Expand all | Collapse all

16" Recycled waterline model

  • 1.  16" Recycled waterline model

    Posted 09-27-2018 08:01

    1. I have a recycled 16" waterline that I am modeling to center line elevations, is there a way to 

    convert or provided the field with invert elevations to stakeout to? 


    The only way that we were able to make it work for us is to create a trench at invert elevations

    and explode it in order to get the invert grades at center line. (this does not hold stationing)


    2. Is it possible to attach a pipe to an alignment without creating nodes for each grade break? 

  • 2.  Re: 16" Recycled waterline model

    Posted 10-01-2018 16:30

    1) It depends on how you have defined this - if you use the Pipe Command to define each segment then it can easily be changed to display Elevations at Invert, Crown, Centerline etc. If you define it using the Create Utility Line Command then depending on whether you have elevations only at the two end points or at intervals / defined locations along the pipe then in the case of end points only you can change to display At Invert (Properties Pane) but for a Multi Node Multi Vertical Points along the line, it currently only works at Centerline and it cannot be converted to Invert.


    In BC-HCE all Pipes are entered using one type of data (Invert, Crown, Centerline) but all are stored at Centerline. When you query the Properties it can easily show Centerline (the native storage), in the case of simple segment pipes (node to node) it can display or output at Invert, Center or Crown, but on Complex Multisegmented pipes between two nodes, we can only display and output at Centerline. When you output a DXF of the Pipe it will come out at Centerline but you could reimport that and then offset it by the Pipe Radius to get to Invert and then provide that to the Field Crews. Alternatively you could change the elevations of the Pipe Centerline to those of the inverts and while the Pipe will be wrong in the model the elevations would follow at Invert (I dont like this solution).


    2) Yes - if you use the Create Utility Line command as opposed to the Create Pipe command, it will create you one node object at the two end points and then each node of the line will just be a Bend or Grade Break in the Pipe itself. Each Node has to be in the Pipe to give it its position and elevation. Note if you don't add Elevations to the Nodes along the line then the Elevation between the two endpoints will be computed using Linear Interpolation from the two provided elevations.


    This command was created to create objects like Water Mains that follow a Curvilinear Path and where the Elevations are often defined at Centerline and not Invert. The command can however be used for any type of Pipe, Cable or Conduit / Culvert / Trench etc. but it works only at Centerline Elevation unless the only elevations provided are at the two end points.


    If you have a pipe that is defined at Invert that follows a curvilinear path (multi segment path) and where there are many VPIs along the path then you should adjust the elevations of the pipe provided at Invert to Centerline before creating this type of object.


    The product team are aware of the need to define multisegment pipes at Invert and Crown as well as centerline - so I hope that this need can be addressed at some point in the future.


    If you need them at Invert, are prepared to model each segment individually and dont want Nodes at each endpoint, I create a Site Improvement called Null Termination as a Headwall Object and use the sphere object as the indicator but make it very small so it is not visible (0.01 size) but Red so it appears as a Dot, and if you dont want those computed in Takeoff make them Existing when you create them so they dont get counted or just ignore the Count of null Terminations in the Takeoff Report - that way you can model each segment of the pipe - they will appear disconnected on screen but you will then be able to define them at Invert. If you want them to look continuous, make the sphere the External Diameter of the Pipe and it will look somewhat like a Joint if you are concerned about the visualization elements here.


    Sorry that this is the best answer I can give you at this time.



  • 3.  Re: 16" Recycled waterline model

    Posted 10-01-2018 16:49

    You will also find that when you use the Create Utility Line command that you will also create an additional Linestring along the centerline of the pipe (it has a type Linestring and it is placed on Layer 0). You can offset that line by the Pipe Radius using the Change Elevation Command to take that Linestring down to Invert Elevation and use that for your Stakeout needs. the video below shows this workflow.


  • 4.  Re: 16" Recycled waterline model

    Posted 10-02-2018 12:06

    Thank you for your help.

    How can we offset the pipe perpendicular to the slope and create a new alignment for staking? The pipe on this particular job is already formed and we don't have much room for field adjustments. After a second look, trench creation does not account for the horizontal movement of grade breaks from centerline to invert. Currently we can calculate the horizontal offsets manually and we have also come up with a method of offsetting perpendicularly using alignment profile view.

  • 5.  Re: 16" Recycled waterline model

    Posted 10-02-2018 13:37

    Good question? .....


    Is the slope variable along the line or constant?


    If Constant you would have to compute the Vertical Offset using standard Trig from the Slope and the Perpendicular offset that you are given and then offset the line vertically by the adjusted amount.


    If the slope is variable this is more of a challenge - where do you want the nodes of the original line after the offset - vertically below the original nodes or at a computed offset based on the inbound and outbound slopes? 


    How do you want to handle a >180 degree and <180 degree grade change (the less than 180 degrees is more of a challenge than the greater than 180 degrees grade change. 


    You can for sure make the Pipe a HAL/VAL and then create a VAL for it at the given line and then use the Offset Line in the Profile Editor for the offset and that will offset perpendicularly. 


    I noticed that some of our Drawing and Snap tools dont work well in the profile View so we need to do some work there, but at least the Offset Line works - Use Right for Below and Left for Above, and specify the Offset (as your Perpendicular offset) and you will see that it offsets correctly and adjusts at the grade break points. You will however find that at the start and end of the line depending on the Outbound or Inbound slopes at those locations that the New Vertical is offset from the start and end station - so you will get a short element of no elevation or no location of the line. You can use Trim / Extend and then use the Extend by Distance function to extend the new profile by an amount like 1'.


    Once you have the line correct in the profile View you can then edit the HAL and create a second VAL for it and then append the new profile to it to create a HAL / VAL that is now a 3D line at the desired elevations. You can then use that to build a Corridor, a Trench or a surface model as you need.


    Hope this helps



  • 6.  Re: 16" Recycled waterline model

    Posted 10-02-2018 15:12

    This is the approach we took and it works out pretty well. Thanks again for your help Alan.