Use the View tab > Appearance panel > Line display menu to specify how lines are displayed in the Graphics window.
Turning 2D View — Select this option to a 2D cross-sectional view for turning parts, or deselect it to show a 3D view.
Hidden Line — When using a wireframe view, select this option to hide lines on the back of surfaces and solids, or deselect it to show all surface lines.
Draft Hidden Line — When using a wireframe view, select this option to show lines on the back of surfaces and solids as broken lines.