Swarf
Swarf 5 Axis Milling is a side cutting process. It's perfect for parts with beveled edges and tapered walls. The toolpath is calculated as if there was a straight edge across the 2 edges that define the surface. As long as the face between those 2 edges is straight, you can use a Swarf cut to machine it.
Multi-Axis Contour
Multi-Axis Contour is used to machine 3D curves that lie on the face of the model. These can be actual edges from the models faces, or 3D curves that have been projected onto the face of a model. Inventor HSM will create a toolpath that follows the selected curve/edge, while keeping normal/perpendicular to the surface of the model. Additional options will allow you to tilt the tool forwards or sideways. While you can compensate Left or Right of the selected curve, normally you would machine directly on Center of the curve.