To mill a 3D surface, you must create a Surface milling feature from the surface(s). A Surface milling feature enables you to generate toolpaths using a number of 3D toolpath techniques.
A 3D surface milling feature is made up of one or more 3D milling operations. For example, a single feature may both rough and finish the part surfaces. The New Feature wizard helps you create a feature and its initial operation. After the initial feature is created, you can edit the feature to further control how it is manufactured, or add additional operations.