Insert Arc Graphically (Center, Radius and Angle)

Enters an Arc graphically using the mouse by specifying Center, Radius and Angle.

An arc is part of a circle. An Arc can be defined either by a) three points on its circumference, b) a center, a radius, two angles (starting and final angle) and its orientation, or c) by two points, a center, and a radius. Arcs can be entered either graphically using a cursor (most common) or using the New Arc dialog window. When entering a new arc or circle graphically, a user must select the command Insert->Domain Geometry->Arc->Graphically from the menu, or one of the following commands: (a) Arc by 3 Points, (b) Arc by two points and radius, or (c) Arc by Center, R, and Angle from the Insert Object part of the Domain Geometry version of the Tool Bar on the right side of the View Window, and then enter the arc using the cursor.

Once a command for defining a new arc using center, radius and angle is selected, a cursor in the View Window will become a cross with a small empty circle in the middle. The coordinates of the location of the cursor will be displayed next to the cursor and on the Edit Bar, which will automatically change to the one displayed below on the left. The Edit Bar will also show, which point and curve (their numbers) are being defined and what reference coordinate system (the current coordinate system, the grid origin, or the last inserted point) is used. After the center is defined, the cursor will change for the definition of a radius. Finally an angle is defined while the Edit Bar is changed as shown below on the right. The Edit Bar also displays the angle size (A) and a step (dA) in which it can be increased. The process of defining a new arc is ended by pressing the Esc keyboard button, the right mouse button (see the Help part of the Edit Bar), or clicking the Stop button on the Edit Bar.

An arc can be entered graphically using several ways:

• Three points
• Two points + (a Height, an Angle, or a Radius), see Edit Bar options
• A Center, a Radius, and an Angle

All these ways lead to the creation of three definition points of an arc, whose indexes are displayed in the Edit Arc dialog window.