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.