Abstract: A method, apparatus, and system provides an integrated viewer with one user interface and one API provides the ability to view, program, redline, and measure DWF and DWG files. In accordance with one or more such embodiments, the present invention provides an intelligent drawing redlining tool for easily and quickly drawing or annotating a drawing. For example, using the tool, a user can click the mouse over the first point of an arc segment. A bulge spacing function may then be utilized to define the length of an arc (also referred to as bulge spacing). In accordance with one or more embodiments of the invention, the bulge spacing function comprises holding down an arc defining key such as the <SHIFT>key while the second point of the arc segment is selected. Thereafter, the bulge spacing of the first arc segment (the distance of the arc between the first and second points) is utilized for the remaining arc segments of the enclosed polyline/path.