Angle from 3 points

Purpose#

Dimensions an angle from three clicked points: the vertex and one point on each of the two legs. No lines need to exist for this, and the legs do not have to be selectable individually — which makes the angle at a bend of a polyline, between two hole centres or between three free points measurable. If two selectable lines are present, the angular dimension of the Dimension command is the shorter route; the tooltip of the button says so too: Only needed when there are no lines, or when the lines cannot be selected individually; otherwise use «Dimension and click two lines.»

The result is an ordinary angular dimension: it can be selected, moved, inspected in the Properties panel, printed and exported like any other dimension. New in program version v3.0.32.

Access#

• Ribbon: group Annotate, list of the split button Dimension, entry Angle 3P Angle from 3 points (6 in the picture at Dimension).
• Classic toolbar: list of the split button Dimension, entry Angle 3P.
• Command search : type Angle from 3 points.

The command has no shortcut key. When it starts, the snap mode switches to automatic (status bar Dimension — snap mode → automatic); when you leave the tool the program restores the previous snap mode.

Procedure#

1. Click the vertex — the point where the two legs meet. The status bar reports Angle from 3 points: click a point on the 1st leg….

1. Click a point on the first leg. It may lie anywhere in the direction of that leg; its distance from the vertex does not affect the angle. The status bar then reports Angle from 3 points: click a point on the 2nd leg….

1. Click a point on the second leg (Position the dimension arc and click…).

1. Place the dimension arc. The distance of the pointer from the vertex is the radius of the dimension arc, its direction the position of the text. A click sets the dimension (Angle dimension from 3 points placed); the tool stays active for the next angle.

Esc cancels the current angle and ends the tool.

Which side, which angle#

The side of the last click decides which of the two angles applies: between the legs the enclosed angle, opposite it the angle over 180°. The two add up to 360°. The choice is kept even if the geometry moves later — the dimension arc stays on the side where you placed it.

Points that stay attached to the geometry#

If a click sits on a point snap — endpoint, midpoint, centre, intersection or tangent point — the dimension remembers that point on the element. If the element is later moved, rotated or changed at a grip, the angle follows and shows the new value. A click into empty space stays a free point and stays where it is; the angle then does not change with the geometry. This works exactly like the point-to-point dimension (Dimension). The snap types and their keys are listed under Snap mode.

Hints at the pointer#

Since program version v3.0.33 the tool says at the pointer what the next click will do: click the vertex, 1st leg, 2nd leg and, before the last click, Place the dimension arc with the addition The side decides: between the legs = enclosed angle, opposite = angle over 180°. The same steps appear in more detail in the instruction field (∠ Angle from 3 points), the running command and the message in the status bar.

left half

right half

When a point does not work#

Two inputs cannot be used; the tool then stays in the same step and waits for another click:

All messages of the tool are listed under Dimension messages.

Options#

The dimension is always driven: it measures the angle and does not force the geometry to a value. After placing it — unlike the angular dimension over two lines — no Edit dimension dialog opens. Open it when needed with a double-click on the dimension and change prefix, suffix, tolerance and decimal places there; text height, unit and arrow sizes are in the attribute panel (Edit dimension).

To make the angle driving, that is, to force the geometry to a value, only the angular dimension over two lines will do: there the program can rotate the second line about the intersection (Modes). Three points alone do not say what should move.

Extension lines are drawn up to the clicked points. Layer, Z level, colour and print behaviour follow the defaults for new dimensions like any other dimension (Dimension settings).

Keys#

Related commands#

• Dimension Dimension — angle over two selectable lines, can be driving
• Arc length dimension Arc length dimension — arc length instead of angle
• Explode Explode — split a polyline into lines and arcs if the legs should be selectable individually
• Measure Measure — read an angle without creating a dimension