To draw a three-point arc

1. Click the Arcs > Arc (Three Point) icon , or choose Arcs > Arc (Three Point) from the Keypoint Curve Toolbox.
2. Click the start point of the arc, or type a 3D coordinate to place the point exactly.
   

   If you click the endpoint of an existing keypoint curve, the new arc attaches itself to the end of that curve. Dragging the common endpoint moves both curves.

3. Click a second point to lie on the arc, or type a 3D coordinate to place the point exactly.
   
   • Click the to add the point freely.
   • Click the to align the point horizontally to the first point.
   • Click the to align the point vertically to the first point.
4. Click the end point of the arc, or type a 3D coordinate to place the point exactly.
   
   • Click the to add the point freely.
   • Click the to align the point horizontally to the first point.
   • Click the to align the point vertically to the first point.

   As you drag the end point, the Arc (Three Point) tool displays the radius of the arc in current linear units.

Arc (3 Point) Options

Degree

Specifies the degree of the curve. The values range from 2 to 7. The default is 6.

Spans

Specifies the number of spans in the curve. The values range from 1 to 14. The default is 1.

Note

The sum of the degree and number of spans cannot exceed 16. When creating rational geometry, as set in Preferences > Construction Options, the Spans option is not available.