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Modeling from DWG Files

  • 1.  Modeling from DWG Files

    Posted 06-06-2019 09:35

    I got this email this am from a Dealer in Europe and I thought it was worth sharing as it is pretty typical of what we are seeing from AutoCAD / Civil 3D and even Bentley these days

     

    Dealer E=mail

    I have a pretty ugly dwg from a customer.

    Once I switch off the layers that are not required I get something that doesn’t really lend itself to creating a surface from it.

    Is there anything I can do in TBC that will remove the upstands and allow me to create a road surface.

     

     

     

    I responded as shown in the answer and video below - hope you find this useful

     

    Alan



  • 2.  Re: Modeling from DWG Files

    Posted 06-06-2019 10:09

    You will see that if you click on lines in 3D that there are both CAD Polylines and CAD Lines in most locations - The CAD Lines are what you want - the CAD Polylines are the Closed polygons and they are useless for anything other than snapping points - but the CAD Lines are only following the Top of Surface elements and you can use those to form models from. You should relayer the Circles and CAD Polylines (use Advanced Select to eliminate them from your "Usable Data:

    These are on C-Markers Standard and C-Shapes_Border Line
    You can make surfaces out of these lines, however because there are nodes vertically above and below each other you will get some Flags on some elements - Use Trim / Extend Lines and Trim the lines that are problematic by Distance say 2 or 3mm to eliminate the vertical faces - it is time consuming - you could also draw a longitudinal line between nodes and then offset by a mm etc as an alternative approach to the same issue - same for Vertical Lines - if you need to trim them back you can either use Break and Delete or you can Trim them by a distance and that will shorten them
    If you add all the "Section Data" for each Surface into a Surface Model, and then add the Road Alignment to it, you can change the Surface Properties ti Alignment Based and then you can apply the Densification to it in Properties also to densify the data through the curves (Hz and Vt) to build a better surface from the data provided - I would just do the Top and Bottom Surfaces most likely and If I needed the Material Layers then I would add those surfaces as Surface Instructions to a Corridor Model and then I would most likely build the Subgrades using the Corridor Modeling Tools but coming off the Surface Instructions / intersecting with the surface instructions.
    You also have to ask yourself is the Data Prep Process from the CAD file going to be quicker than building a Corridor Model from Scratch - these types of road are typically pretty simple and don't have a lot of cross slope variations
    Here is a video of how I would tackle this
    Hope this helps
    Alan


  • 3.  Re: Modeling from DWG Files

    Posted 06-06-2019 12:02

    Every time i get a dwg or surfaces from a customer wich looks like everything already is done i get happy. 

    -This is perfect! all i have to do know is just to put this together and export it to a machine, 20min of work, nice....

     

    After doing this for about 10 years now i know that EVERY time i try this i end up (after many hours working with the data i thougt was ok) doing my own new corridor and my own models (of course in the middle of the night because its not enough time). When i do that i also have an easy work when the customer starts changing stuff. This is always the best way to do it, i promise. Its easy to create a new CL and a corridor. 

     

    Use the customers data as something to do your own data from, always, thats my tip.