• Civil 3D Surface Points

    Matt Kolberg
    Technical Consultant — INFRA/GIS at SolidCAD  

    Easily differentiate points appropriate for a surface model from those that are not.

    A typical topographical surveys consist of hundreds or even thousands of points, most of which must be added to the definition of a surface model.  Some of these survey points are not appropriate for use in defining surface models.  Such as those points not taken on the ground.

    Many Civil 3D users use a special point group to exclude those points that are not appropriate for surface models.  The group is defined by including the survey points, but excluding those points whose raw descriptions match those in the list.

    This works well, but it will fail when the surveyor shoots a point with a non-standard code, that point does not belong in a surface model, and this is not communicated with the design staff.

    Consider this technique instead:  Define description keys for all points and define the Format column as usual with one exception: add a special character, such as a plus, to the end of those points which are appropriate for modeling surfaces.  Points that are not shot on the ground are devoid of this plus at the end.

    Then define the point group with only one custom setting, Include points whose Full Description ends with that special character, in this case a plus.

    When a surveyor in the field encounters a feature which requires a new code, and that point is appropriate for a surface, they can simply append that special character to their raw description.  If no communication between them and the office staff takes place, that point will automatically be included in the point group and therefore in the surface model.

    In the rare case where a point normally appropriate for a surface model is not appropriate for a single shot, the surveyor can append another special character to exclude that point from the surface.  MHD-  Then the surface point group can exclude points whose raw description ends in that character.

    Manhole where the lid is above ground…