NURBS Curve

Create a NURBS curve, which is a free-form curve.

1. On the Geometry ribbon, select the NURBS tool.
   
   
   Note: The tool may be hidden in a dropdown menu. To access the dropdown menu, you can do one of the following:

   • Click and hold the currently displayed tool (Blend, Helix Curve, Extend Curve, Face Curve, or Divide).
   • Select at the lower right corner of the currently displayed tool (Blend, Helix Curve, Extend Curve, Face Curve, or Divide).
2. Optional: In the guide bar, select a Degree.
   Tip: Enter a higher degree for a smoother curvature.

   Note: The degree of the curve depends on the number of control points. For example, a Degree 3 curve would need at least 4 (3+1) control points.
3. To place the control points, click existing vertices, sketch points, or reference points.
   Note: To edit after creation, right-click the NURBS curve in the History Browser (F6), and then select Edit.
4. To edit the NURBS curve, adjust the control points, degree, and other options.
   Note: To extend the NURBS curve, click the plus sign near an endpoint. To insert a control point within the NURBS curve, click a plus sign on the control polygon (dotted gray line).

   In the microdialog, you have the following options:

   Option	Description
   Smooth	Close the curve smoothly.
   Cusp	Close the curve with a sharp corner.
   Open	Open the curve at a selected control point.
   Maintain/Break Snap Reference	Link the control point to a snap point. The shape of the NURBS curve will change based on the position of the snap point. Or break the link between the control point and the snap point.
   X	Enter the x-coordinate of the control point.
   Y	Enter the y-coordinate of the control point.
   Z	Enter the z-coordinate of the control point.
   Weight	Add weight to a control point to give it greater influence over the shape of the curve.
   Reset	Clear all selected features and restore the default values.

5. Right-click and mouse through the check mark to exit, or double-right-click.