Fixing CSG error locations

I have had an issue when building a faulted geological model using borehole data. When I developed the initial unfaulted mode, there was no issue at all and it processed fine, however when I use the same data to create a faulted model, several fault blocks do not process correctly, with units sitting side by side instead of on top of one another. This is despite having "snap to data" switched on. I have received an error saying that the meshes are not closed, and data added into the "Points" folder showing "Surface Chronology CSG Error Locations" which I can view, but not do anything with. Is there a simple fix for this?


  • MustafaKaplan
    Hi James,  

    Just a guess;

    Could it be related to boundary filter? You may have disabled the filter for contact points and they interfere with each other across fault surface?

  • LisaChanderman

    Checking if there is any update on this. I have encountered this problem once last year and had to re-do my entire geological model to resolve. Have encountered it again - because I reloaded Data. Everything worked fine up until I reloaded data to update my un-faulted geological model. Does LF perhaps have an actual explanation for what causes the error and how our workflow should be modified to prevent it from occurring? Not sure how the locations are meant to assist the user? Thanks
  • GabrielAliaga
    Hey Lisa,

    I'll just add that I've also run into this issue out of nowhere a couple times now. I can upload data and a surface that shouldn't have even been affected runs into a CSG error.

    I have been able to fix the error every time (eventually...)  by taking a close look at the location and seeing if there are any polylines nearby that I can adjust a little bit and reprocess while crossing fingers. Sometimes I can tweak it by just the slightest bit (won't cause any meaningful change in the model) and it fixes the error. 
  • ThomasStrauhal
    I just want to raise this topic again since I am facing this error message for several models as soon as I add faults.
    The procedure, Gabriel presented usually 'fixes' the problem. But after ~10 iterations, since adaptions of polylines usually causes error locations at slightly different locations....
    Any further suggestions or a fix for this problem would be appreciated.
  • SeanBuchanan
    SeanBuchanan Posts: 17 mod
    Hi All, 

    Constructive Solid Geometry (CSG)  errors can be challenging to resolve as they typically occur in highly complex models. If you have encountered a CSG error, you can try the following to resolve it.
    ** This is not an entire workflow, but rather separate changes you can make to see if it resolves the CSG error. 
    1. Turn Adaptive resolution on or off (i.e. whichever one it currently isn't).
    2. Change the Resolution of the surface by a small amount. Often +/- 0.1-0.5 is enough.
    3. Try to use a consistent Resolution throughout the model, as much as possible.
    4. Enable Merged output volumes (double-click the Geological Model, in the General tab).
    5. Change the Snap to data option (or increase the Maximum snap distance if it's enabled) in the model's General tab.
    6. Ensure there are no duplicate data points used as values, extents, or intervals.
    7. Move one of the inputs by a small amount. Often moving a drillhole by 5cm will fix the issue, and not materially affect the precision of the model.

    Additional Information on CSG error can be found from this Knowledge Base Article: