ApplicationSettings.FreeformDrawingSmoothing Property (Visio)
Determines how precisely mouse movements are smoothed when drawing a spline. Read/write.
Setting the FreeformDrawingSmoothing property is equivalent to setting the Smoothing option on the Advanced tab in the Visio Options dialog box (click the File tab, and then click Options).
Possible values for the FreeformDrawingSmoothing property range from 0 (Tight) to 10 (Loose). The default is 5.