Extrapolating Curves

You can extrapolate a curve. Extrapolation extends an element by a specified amount respecting tangency or curvature conditions.

Note: The command is also available in the context toolbar.

Before you begin: Create a 3D shape containing a curve.
  1. From the Modify section of the action bar, click Extrapolate .
  2. In the Boundary box, select an endpoint on a curve.
  3. Optional: In the Extrapolated box, select the curve to be extrapolated.

    Note: This step is only required if the command is unable to automatically compute the curve or if you want to manually select it.

    The curve selection appears in the Extrapolated box. It can be a wire, an edge, a curve, or a line.
  4. In the Limit at boundary frame, select the extrapolation type in the Type list.
    OptionDescription
    Length Enter the value in the Length box or use the handles in the work area.
    Notes:
    • Enter a positive value.
    • In Curvature mode, the length is the distance of wire obtained through tangent extrapolation re-limited by the plane created at the given length from the chosen extremity. This plane is used to split the extrapolated curve.
    Up to element The Up to box is enabled. Select an element belonging to the same support as the curve to be extrapolated (curve, surface, or plane).
    Important: The element must intersect the curve to be extrapolated.
  5. In the Continuity list, select the continuity.
    • Tangent: The curve and the extrapolation are connected with tangent continuity at the selected endpoint.
    • Curvature: The curve and the extrapolation are connected with curvature continuity at the selected endpoint.


    Length extrapolation in Tangent mode

    Length extrapolation in Curvature mode


    Up to extrapolation in Tangent mode

    Up to extrapolation in Curvature mode


    Extrapolation without support

    Extrapolation with a support
  6. Optional: In the Second limit frame, select the extrapolation type and value for the other curve end.
    The curve is extrapolated individually at each end.

    Note: When both sides are extrapolated, the Assemble result check box is selected and grayed out.
  7. Click OK.

    Note: Select the Assemble result check box to assemble the extrapolated curve with the original curve.