You can set the style and weight of lines for various kinds of edges in drawing documents only.
The line font options are available only
if the active document is a drawing document.
To set the style and weight of lines in drawings:
Click Tools, Options, Document Properties, Line Font.
Change the settings for one or more type of edge, and click OK.
Select an edge type from the list: Visible Edges, Hidden Edges, Sketch Curves, and so on.
Choose a style from the list: Solid, Dashed, Phantom, Chain, and so on.
Select a style that defines the ends of edges: Flat, Round, or Square.
Choose a thickness from the list: Normal, Thin, Thick, and so on.
Displays the selected line font.