The Convert menu contains options for converting between arcs, lines, and Bezier curves, as well as converting blends and clipping paths.
Convert Beziers to Arcs
This command will convert the selected object's vectors into arcs and lines, removing any bezier curves that may be used in the object.
Note that bezier curves can describe much more complex shapes than simple arcs and lines, so there is not a straight 1:1 conversion from bezier curves to arcs. In fact, there may be many arcs for one bezier curve.
If you need to create arcs and lines for export to a DXF file that would be used for a router or channel letter bending machine, then you should use Optimize Vectors since that function will remove redundant nodes.
Convert Arcs to Beziers
This command will convert the selected object's arcs into bezier curves, which are often easier to edit and distort than arcs. Oppsoite of converting Beziers to Arcs, this command will likely result in considerably fewer vectors, as many arcs can be converted into a single Bezier curve.
Convert to All Lines
This command converts all arcs and bezier curves in the selected graphic into multiple lines or "chords," according to the current curve resolution settings used to display such arcs and bezier curves, as specified in the global Options dialog.
An Arc Resolution of 2 degrees will convert a circle to 180 short lines.
Convert Lines to Arcs
This command will convert an object that is only lines into one that contains arcs and lines. It tries to determine where a series of lines actually form an arc and substitute an arc in their place.
Convert Flat Blend to Simple Fills
Use this command to convert all flat blend objects in the layout to simple fills.
Convert All Clippings Paths to Normal Paths
Use this command when you have imported an EPS/PDF file that use clipping paths extensively, but become difficult to manage. This creates unfilled graphics.
Convert All Clipping Paths to Normal Filled Paths
Use this command when you have imported an EPS/PDF file that use clipping paths extensively (instead of simple fills), but become difficult to manage when imported. This creates filled graphics, where it is assumed that there is a simple filled rectangle being clipped and the actual graphic is the clipping path. This may not work in all cases.