This submodel contains the classes and associations required to support the definition of drilling targets. A directional well can have one or more objectives. The most obvious objectives are the targets. These can be geological features such as faults or pinch-outs, other boreholes (as in relief well drilling) or indeed any combination of these. A target is defined as being a shape in three-dimensional space with a reference point. It is expressed in terms of a particular coordinate system and may describe the geologic feature that it represents.