• Industries
  • Products
  • Buy
  • Services & Support
  • Communities
  • Discussion Groups

    AutoCAD Civil 3D

    Reply
    Active Member
    Posts: 8
    Registered: ‎01-25-2013

    Datum Surface not Consistent

    237 Views, 5 Replies
    01-29-2013 06:13 AM

    Anyone know why a Datum Surface will correctly follow the bottom links of a corridor at 1 location but not another?

     

    Please see attached.  The 2 stations shown use the same assembly and are in the same region. Some locations appear to be correct, while a few other locations "skip" points they are supposed to hit.

    Please use plain text.
    *Expert Elite*
    johnm
    Posts: 1,717
    Registered: ‎11-13-2006

    Re: Datum Surface not Consistent

    01-29-2013 08:19 AM in reply to: cman24

    Did you toggle the overhang correction to 'bottom links'?

    John Mayo, PE
    C3D 2012, RD 2012
    Win 7 64, Core i7,
    6 GB RAM, Quadro FX 1700
    Please use plain text.
    Active Member
    Posts: 8
    Registered: ‎01-25-2013

    Re: Datum Surface not Consistent

    01-29-2013 08:22 AM in reply to: cman24

    Yep. 

     

    I am hoping I am just missing something simple like that, but I just can't figure out what it is.  It wouldn't be so frustrating if the error occured at every location, but the fact that it works at some and not others is just confusing.

    Please use plain text.
    Mentor
    Posts: 156
    Registered: ‎10-31-2006

    Re: Datum Surface not Consistent

    01-30-2013 07:46 AM in reply to: cman24

    If you look at the surface triangulation in plan view you will probably see that the tin lines are not created correctly along the vertical portion of the datum.   Two ways to fix this:

     

    1. Reduce the frequency distance.  This will output more link data to the surface, which should cause the triangles to form correctly between the adjacent corridor sections.

     

    2. Or, add feature lines from the top and toe point codes.

    AddCorridorFeaturelinesToSurface.jpg

    David Zavislan, P.E. | CAD Manager / Associate | NV5 | www.nv5.com
    Please use plain text.
    Employee
    Posts: 627
    Registered: ‎08-25-2009

    Re: Datum Surface not Consistent

    01-30-2013 08:46 AM in reply to: david.zavislan

    What subassembly was used to create the curb? It looks like you have three points at the same place vertically and this is causing the TIN "issues". We've tried to make our internal subassemblies have a very slight offset (moving to away from the centerline) to avoid these conditions.

     

    Regards,

     

    Peter Funk

    Autodesk, Inc.



    Peter Funk
    Autodesk, Inc.

    Please use plain text.
    Active Member
    Posts: 8
    Registered: ‎01-25-2013

    Re: Datum Surface not Consistent

    01-30-2013 02:33 PM in reply to: cman24

    This is a subassembly from our Client (WisDOT).  I've experienced issues before related to the vertical stacking of points.  There is a slight offset with this subassembly, but maybe it's not enough of an offset.  I just found it odd that it worked in some locations and not others.  I think I will just have to apply a work-around like what David suggested until I can get an update to this subassembly.

     

    Thanks for the help.

    Please use plain text.