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# Drawing Circles

A circular boundary can be easily created in RS2.

NOTE: A circle in RS2 is actually made up of straight line segments.

To create a circle:

2. Select Circle from the right-click menu, or type the letter i followed by Enter in the prompt line.
3. You will see the Circle Options dialog, in which you can choose:
1. Circle Definition MethodCircle to polyline conversion method
4. Make your selections in the dialog (see below for details), and select [OK].

5. Enter the circle as described below.

## Circle Definition Method

In the Circle Options dialog, there are two different methods available for defining the circle - Center and point on circle OR Center and Radius.

### CENTER AND POINT ON CIRCLE

If you chose Circle Definition Method = Center and Point on Circle:

1. Enter the circle center (you may use the mouse or the keyboard).
2. As you move the mouse, an interactive circle will be drawn on the screen (the circle radius will be displayed). Enter any point on the circle, graphically with the mouse, or with the keyboard, and the circle will be added to the model.

If you chose Circle Definition Method = Center and Radius:

1. Enter the circle center, with the mouse or the keyboard.
2. The circle will immediately be added to the model, using the Radius which you entered in the Circle Options dialog.

## Circle to Polyline Conversion Method

A circle in RS2 is actually made up of straight line segments. In the Circle Options dialog, you may select one of two options for converting the circle into a polyline:

• Number of segments - you can specify the number of segments in the circle. In this case, the exact number of segments will be used. All segments are of equal length.
• Approximate segment length - you can specify an approximate segment length. RS2 will automatically determine the number of equal segments which gives (approximately) the desired segment length. The actual segment length may be different from the approximate value you have entered.

## Creating an Ellipse

To create an elliptical boundary:

1. First create a circle as described above.
2. Use the Scale option to change the shape of the circle into an ellipse.