Automatic Feature Recognition
The FeatureWorks software attempts to automatically recognize and highlight as many features as possible.
The advantage to this method is the speed at which features are recognized because you do not select faces or features. If the FeatureWorks software can automatically recognize most or all of the features in your model, then use Automatic Feature Recognition.
Interactive Feature Recognition
You select the feature type and the entities that make up the feature that you want to recognize.
The advantage to this method is the control that you have over the features that are recognized. For example, you can decide if you want to recognize a cylindrical cut as an extrusion, a revolve, or a hole. Additionally, you can determine the location and complexity of the sketches of your features by the faces and edges that you select.
You can use step-by-step recognition using both of these methods.