2D line segments and arcs are individual curves. A coincident constraint joins their endpoints. When you move a curve, all joined segments and arcs also move.
3D lines and arcs are commonly used to create a path for 3D sweep features. 3D sweep features define routed parts such as tubing and cabling. Use the 3D Line command to create straight sections. Use the Arc and Bend tools to create curves.
The 2D Line tool creates straight line segments, with or without a tangent or perpendicular arc or line at the end of segments.
The 3D Line tool lines in 3D space, with or without bends between segments.
The Arc tools create arcs by placing three points — a center point and two endpoints.
The Bend tool lets you place tangent corner bends on lines in a 3D sketch.
Enable or disable automatic bends at the application level, and set the default bend radius at the document level.
Enable or disable creating geometry along the X, Y, or Z axis.
To enable Ortho Mode, press the icon in the status bar or use the shortcut Ctrl + R to toggle on or off.