Drawing arcs by BCE (Beginning-Center-End)

You can construct an arc by sequentially positioning three points (starting, center and end), as well as the radius of the arc and the angle between the two radii connecting the center with the beginning and the end points of the arc, respectively.

Control points

An arc defined by a beginning, a center and an end has four control points: the starting and end points, the center point of the circle the arc belongs to, and a point lying in the middle of the circumferential length of the arc. While you are drawing an arc by BEC, the following pointers appear:

About to draw the starting point of the arc.

About to draw the center of the arc.

About to draw the end point of the arc.

NOTE: The contextual edit bars, attributes and tabular area presentation, as well as the procedures for modifying and repositioning of an arc are the same for all arc-drawing modes except for arc by BEH.

To draw an arc by BCE

Do any of the following:

On the Objects toolbar, click Arc by BCE .
On the Objects menu, point to Arcs, and then click Arc by BCE.
Press CTRL+D+A+B+C.

(Optional) Snap the beginning point of the arc to another object or point.
In the graphical area, click where you want to draw the starting point of the arc.
(Optional) Snap the center point of the circle the arc belongs to, that you are about to place, to another object or point.
Drag the mouse in the desired direction and draw the center point of the circle the arc belongs to.
To finish the arc, do the following:

Snap the would-be end point of the arc.
Point to where you want the center to be, and then click.
In the contextual edit bar, in Radius and Angle enter respective, press ENTER, and then click anywhere in the graphical area.

NOTE: To switch the directions in which the arc is being constructed, before you draw the end point, press CTRL.

TIP: Point snapping during drawing of arcs

You can use snapping while drawing arcs. Snapping guides you for the correct positioning of arc's points relative to the x- and y-axes. See the example below and try it in the program. The example applies for the drawing of arcs of the types CBE and BEC.

The beginning point is drawn and you proceed with placing the arc center. The center is about to be placed (indicated by the mouse pointer icon). Note that the line is still not parallel to the x-axis.

When the line becomes parallel to the x-axis, it snaps (on the screen you can feel a tiny jump in the line) and the mouse pointer changes to an arrow.

After the center has been placed, the end point comes next before the arc is drawn. Here the mouse pointer indicates that the end point is to be added. However, note that the line defined by the beginning point and the end point is not parallel to the x-axis.

When the beginning-point-end-point line becomes parallel to the x-axis, it snaps (on the screen you can feel a tiny jump in the line) and again the mouse pointer changes to an arrow. The paralellness is visualized in the next picture.

The line defined by the beginning and end points is parallel to the x-axis. This is indicated by the horizontal mouse pointer icon just below the figure 2.