Construction lines

Purpose#

These three tools do not draw free segments but derive from existing geometry: the bisector of two lines, a line at a given angle to a reference line, and the perpendicular from a point onto a line. The result is an ordinary line on the active layer that can be changed, dimensioned and deleted like any other.

Access#

• Ribbon: group Draw, triangle on the Line button — entries Angle bisector (2), Perpendicular (3) and Relative angle (8).
• Classic toolbar: drop-down triangle of the line family (1).
• Command search : Angle bisector, Perpendicular or Relative angle.

The tools have no keyboard shortcuts.

Angle bisector#

Angle bisector Halves the angle between two lines. The sequence has three steps:

1. Click the first line (1) — status bar: Click the 1st line of the bisector.
2. Click the second line (2) — Click the 2nd line.
3. Set the length (3): click the endpoint or type the length into field L and press Enter — Set the length: click the endpoint (or L + Enter).

The bisector starts at the intersection of the two lines — even when the lines do not touch and the intersection lies outside them. The side it runs on follows from the two click positions. At the end the status bar reports Bisector created.

Two cases are refused: parallel lines (The lines are parallel — no bisector possible) and exactly opposing lines (Degenerate angle (lines opposing)).

Relative angle#

Relative angle Draws a line whose angle is counted not from the horizontal but from a freely chosen reference line — the usual case for angled connections. Three steps:

1. Click the reference line (1) — Relative angle — step 1 of 3: click the REFERENCE LINE the angle is measured from.
2. Click the start point of the new line (2) — Step 2 of 3: click the START POINT of the new line (object snap is active). Object snap is explicitly active here, so the new line can start exactly on existing geometry.
3. Click the endpoint — or type angle ∠ and length L. Tab locks the angle, Enter draws.

The displayed angle is measured from the reference line, positive counter-clockwise. At the end the status bar reports Line at relative angle created.

Perpendicular#

Perpendicular Drops the perpendicular from a point onto a line. Two steps:

1. Click the point (1) the perpendicular starts from — with object snap, for instance on an endpoint or a centre.
2. Click the target line (2) — Click the target line — the perpendicular is dropped from the point onto it.

The perpendicular ends at the foot point on the line; if the foot point lies outside the drawn segment, the calculation uses its extension. At the end the status bar reports Perpendicular dropped. If the chosen point lies exactly on the line, it reports The point lies on the line — no perpendicular possible.

Options#

• All three tools draw on the active layer; pick up attribute (J) first takes colour, width and line type from an existing element.
• If Create dimension while drawing is on, the new line receives its length dimension (live dimensioning).
• Esc cancels; every result is a separate step for Undo.

Related commands#

• Line — free segment
• Tangents — connections to circles and arcs
• Coordinate entry · Snap mode