Attaching a Circle to an Existing Object

You can attach either the center point or the radius point to an existing object. To do so, you can click on

· an existing point

· a path object (such as a segment, a line, a circle or an arc)

· an intersection of two path objects.

When the Compass tool is in the right place to click on an existing object, that object is highlighted, appearing thicker and in a special color.

Be careful when you want to attach the radius point of a circle to an existing object. It’s not enough to position the circle so that the circle appears to go through the desired point. You must actually position the tool itself over the point or object to which you want to attach before clicking or releasing to locate the radius point.

In the left box f the following illustration, even though the circle appears to pass through the vertices of the triangle, the radius point will be located in empty space. The result is that the radius point will be independent, and dragging either the radius point or any part of the triangle will show that the circle isn’t attached to the vertices.

In the right box of the same illustration, the tool is positioned at a vertex, and the vertex is highlighted. Thus, that vertex will be the radius point of the circle, and the size of the circle will be linked to the position of the vertex no matter how various parts of the figure are dragged.

Circle not attached to vertex

Circle attached to vertex