This invention relates to a method for converting low-level stitch-by-stitch numerical control code embroidery design programs into an outline format which can be edited and modified to generate new design patterns which may be converted back to either stitch-by-stitch numerical control codes or a condensed data format. The invention permits a user to independently vary and modify a large variety of characteristics of an existing embroidery design control program including converting straight line portions of a design pattern to smoothed curves, converting a portion or all of the stitching in a design from one type of stitching, such as satin, bean or tatami, to a different type of stitching, changing stitch lengths in any fill patterns or stitch runs, changing the fill patterns in any fill stitches, adding or deleting automatic underlay stitching, changing the density of stitching in any portion of a design, moving or deleting any portion or point, copying, rotating, scaling, and mirroring any portion of a design, correcting satin segment points which are reversed, changing fill angles, changing the order of sewing segments, and changing the color of any portion of a design.