edge line not display (3d hidden style)

[yiufaipoon]

I have a problem of display some of the edge line in 3d hidden style mode??? I can't plot those edges as well. Below is an example.
any idea ?? thank you.

[SEANT]

Set "Fast Silhouette Edges" to yes.

[yiufaipoon]

Thanks.
Now I can plot(print) all the edge line after I set "Fast Silhouette Edges" to yes and the width set to 1. But it only display part of the edge line from the screen.
When I increase the width of the Fast Silhouette Edges, it helps to display all the edges but the line become too thick. I want all the lines with the same even width.

[yiufaipoon]