The Arc tool allows you to draw a three-point mathematically defined arc in the Trace software.
The /wiki/spaces/FrameShop8x/pages/1942694083 has three points: Initial Position (called an Anchor), Middle Point (called a Handle) which can be moved to change the shape of the Arc, and Terminating Position (called an Anchor).
The /wiki/spaces/FrameShop8x/pages/1942692800 process will convert the Arcs to Splines which are easier to tangify to make cuts smoother.
See: Arc Tool in Trace
See: Arc Tool Definition/wiki/spaces/FrameShop8x/pages/1942694083
See: Splines Definition
See: Convert Arc to Splines Function