Hidden Line rendering is not displaying correctly in front or back views.  Other views are correct.  Attached are some samples and a VW file.  Sample 1 shows what a front view, hidden line rendering should look like.  I had to cant the model a small fraction to get it to render correctly.  Sample 2 is a Front view, hidden line rendering and is showing lines that should be hidden, especially in the bottom center of the model.  Sample 3 is an isometric view of the model.   Any help is appreciated.