Editing Curves Using Control Points  

This task explains how to modify a curve using its control points.

Use the Control Points dialog box to modify the curve according to certain predefined laws.

Open the FreeStyle_01.CATPart document.

  1. Select the curve you wish to edit.

  1. Click the Control Points icon:


The Control Points dialog box appears.


Control points and lines are displayed, along with the 3D compass and the curve degree.

  • If you select a curve that has been created outside the FreeStyle workbench, and the curve is not a NUPBS curve (Non-Uniform Polynomial  B-Spline), the Converter Wizard will be automatically displayed when the curve cannot be exactly converted, see Approximating/Segmenting Procedural Curves. This allows you to control the conversion tolerance. 
    However, when a curve can be exactly converted, such as a spline, or line for example, the Converter Wizard is not displayed, the conversion is done automatically and a message is issued. In this case, the Exact text is displayed on the element for information.

  • Planes and lines are used to quickly orientate the compass in the control points command. Therefore if you select a plane or a line, it will modify the compass orientation.

  • By default all control points and mesh lines are selected. Click a specific point to deform the surface at this point only, or select a set of points using the Ctrl-key or Shift-key while clicking (multi-selection capabilities). The same applies to mesh lines.

  1. Move the pointer over a point or a line.


Arrows are displayed according to the Support and Law options active in the Control Points dialog box:

  • Support defines the type of translation to be applied

  • Law defines the type of deformation that is to be applied when several control points have been selected.

  1. Pull on the arrow matching the direction in which you want to deform the curve.

  1. Use the Dashboard to display the order number directly on the curve, using the U, V Orders icon:


The value is displayed on the curve.

  1. Use the contextual menu to choose the order number for the curve.


If you increase the order number to 11, the result is:

  1. Click OK in the Control Points dialog box to validate the modifications.

Further modification options are available from the More... button of the Control Points dialog box:

  • To perform a quick analysis of the mesh line inflection, select the Inflections option.

  • Freezing of the selected points (no other can be selected) and of the Support option.

  • Dynamic display of the initial curve and of the delta as you pull on the control points.

  • Global selection/de-selection of control points using the Select All and De-Select All icons, without having to click the geometry.