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Draw a construction line, tick the crossings you want, then hide the line.

Menu: Draw > Straightedge | In depth: Compass & straightedge

Two clicks give you a line to work along. Then, instead of leaving that line in the drawing forever, you mark the places on it that matter and let the line itself disappear.

This is how classical construction actually works on paper. The straightedge is a tool, not part of the figure. What you keep is the marks you made with it.

First, the line. Click two points and you get a real, visible line through them, exactly as the Line tool would. It is a genuine object while you are working, so everything crosses it and everything snaps to it.

Then, tick mode. The tool stays on that line and every click now marks it:

• Click and you drop a tick at that spot. Click a crossing and the tick sits on a real intersection point that tracks the crossing; click anywhere else along the line and it lands on a point that rides the line.
• Drag and you strike a piece of the line: a real segment between where you started and where you let go, snapped to points and crossings at both ends. This is the compass-and-straightedge move of drawing only the stretch you need.
• A drag that ends where it began marks nothing at all. No stray point, no empty step in the undo history.

Press Enter or Escape to finish. The line retires: it, the two points that defined it, and every anchor the session created go into a hidden helper group, and only your ticks and struck pieces stay visible.

Points that already existed when you started are yours, not the tool's, and they stay visible. The tool only sweeps away what it brought.

Retired does not mean gone. A hidden host is still a live snap target, so you can keep snapping to that line long after it stopped cluttering the canvas, and everything built on it keeps working. Unhide All deliberately leaves these helper groups hidden for that reason: they are put-away tools rather than things you accidentally hid.

The result is a drawing that reads like a finished construction instead of a worksheet, while every measurement in it is still live and still tied to what produced it.

< Previous: Arc: Center, Start, End | Next: Compass >

• Compass & straightedge: the whole working method, and when to reach for it.
• Compass: the same two phases with a circle instead of a line.
• Unhide All: why it leaves retired hosts alone.