#Line

Key L. Draws a segment or a polyline.

#How

Click the start, click the end — the segment is there, and the next one already follows from its end. A double click ends the polyline, Esc leaves the tool.

#What is added for you

With auto constraints on, a nearly horizontal segment gets a horizontal constraint, a nearly vertical one gets vertical, and an endpoint snapped to someone else's point gets coincident. That is why a freehand outline often comes out almost fully defined.

If the wrong constraint appears, remove it from the constraint list: the geometry itself does not change, it only becomes freer.

#A hint

It is easier to close a polyline back into the point you started from: a closed outline is what a body is made of. An open one is useful for sweeping along a path and for construction geometry.