Intersections: Setting up 2D / 3D Intersections

You can execute mixed intersections between a 2D and a 3D feature class. For example, you intersect a 2D feature class with a view on a 3D feature class. The intersection is calculated using the 2D coordinates where the Z value is ignored, and results are stored as 2D geometry, or 3D geometry with Z=0. An exception is n intersection in a 3D industry model, if the secondary feature class is a point. In that case, the result is the original point with X,X, and Z coordinates.

To execute mixed intersections, you must set up the intersection feature classes manually. As a industry model can be either 2D or 3D, the 2D and 3D feature classes are stored in different industry models. In the industry model where you want to create the intersection (target industry model), you must create a view to access the feature class of the source industry model.

To set up 2D/3D intersections

1. In the target industry model, create the view.
   • Create a synonym to the feature class in the source industry model.
   • Grant SELECT on the synonym.
   • Create a view on the synonym.
2. In the Infrastructure Administrator, do one of the following:
   • Click Enterprise and connect to the enterprise industry model . Open a project.
   • Click File and open a project.
3. Start the data model administrator.
4. Create a feature class from the view. See Creating a Feature Class From a View.
5. Create the intersection.
6. If your target industry model is 2D, set the dimension of the feature class (view) back to its original value TB_DICTIONARY.DIMENSION = 3.

   This is required, because you can only create the intersection if the two feature classes have the same dimension.

7. Re-open the project.
8. Execute the intersection.

Note: To improve performance in a 3D industry model, make sure that your primary feature class is 2D, and your secondary feature class is 3D.