Collision Detection: Creating SVG Polygons for the Game Actors and Writing Code to Detect Collision - Beginning Java 8 Games Development - page 515

Figure 16-22 . Using the Tracer utility in PhysEd to set the Tolerance, Trace mode, Frame mode and Vertices
Once you have the visual result that you're looking for, which is accomplished by
tweaking the various Trace dialog settings, click on the OK button, and you will be
taken back to the PhysicsEditor primary user interface window.
You can then refine your collision polygon structure data point by data point, by
clicking and dragging these points with your mouse, as seen in Figure 16-23 . If you
compare the collision polygon in Figure 16-22 with the one in Figure 16-23 , you can
see I that have refined several of the data points to better conform to the outline of the
sprite.