The Dave and Dan Civil 3D Show

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posted 06/21/07 by Daniel Philbrick Civil 3D and Borehole Data - Part II

I missed completing the Part II of my borehole data post during both the Stanley Cup playoffs and the NBA playoffs. At least I completed it before the World Series.

For review a quick review of Part 1, there are two ways to model borehole data in Civil 3D. The first method is done through User Defined Property Fields and I covered that in Part 1 of this series. The second way of handling borehole data is via an External Point Database. This is the method which I will discuss today. In this method, you override the point elevation based on the values in an external database. To demonstrate this, I have first created an Access database with fields for PNO (Point Number), BH_1 (Borehole Elevation 1), and BH_2 (Borehole Elevation 2).



In this example, we have a database which has 2 elevation values for each point number. Next we are going to override the elevations by creating an External Data Reference which will point to a field in the Access database. The External Data References are created by going to the setting manager, right clicking on the External Data References node, and selection New. The following dialog will appear.



On this dialog, you need to select the external database, and then map the fields in the database to the External Data Reference to be used for the elevations in the drawing. In the previous dialog you can see that I mapped the Point Number (PNO) and the Borehole Elevation value (BH_2 in this example).

Now you need to override the elevations of the points with the elevations defined in the External database. This is done by creating a point group and selecting the “Overrides Tab” . For the elevations, you want to override the elevation and select one of the external data references you created. The following dialog shows the Point Group override for the BH_2 external data reference.



That completes the steps. Now you have a point group where the elevations are being overridden and they are being established from the value in an external database. The key difference between this method and the User Defined Properties is that the External Data Reference data is external to the drawing. When you use User Defined Properties, you need to import the data into the drawing and populate the Property fields.

Using either method, you now can create a surface based on the overridden elevations. Therefore, you can have one point number that has an arbitrary number of elevations assigned to that point. The last step is the create a surface based on the appropriated point group which represents the borehole strata of interest.

Dan

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