Creating Associative 3D Curves on a Scan

This task explains how to create a 3D curve on a scan:

  • either before entering the 3D curve action. In that case, you can select only one scan, 

  • or after entering the 3D curve action. In that case, you can select one or more scans.

  • either graphically. In that case, use the contextual menu Select all points to create a 3D curve on all the points of the scan,

  • or from the specification tree. In that case all points of the scan are taken into account even if you do not activate the Select all points menu.

Open the FreeStyle_04.CATPart document.

  1. Click the 3D Curve icon .
    The 3D curve dialog box is displayed.

  2. Choose the curve creation type.


  • Through points: the resulting curve is a multi-arc curve passing through each selected point.

  • Control points: the points you click are the control points of the resulting curve.

  • Near points: the resulting curve is a single-arc, with a set degree and smoothed through the selected points.

  1. Click OK to create the curve.

A appears in the specification tree.

For further information on the options of the dialog box, please refer to the Creating Associative 3D Curves chapter.

Selecting all points in a scan of cloud

It is possible to select a scan of cloud either in the specification tree or directly in the cloud from the contextual menu.

The Select all points contextual menu is available within the 3D curve action only, i.e. it appears when the 3D Curve dialog box is open.

  • Right-click the Scan on in the specification tree and select Select all points in the scan.

  • Right-click the cloud and select Select all points in the scan.

  Here is an example with Through Points

Contextual Options


Double-click your curve, right-click on the manipulator to display the contextual menu. 

Please refer to the Creating Associative 3D Curves to get the corresponding information.


Only scans of the type "scan on cloud" can be selected since other types of scans might contain too many points.
  • Use the F5 key to move the manipulators into a different plane of the compass. See Managing the Compass.

  • Use the standard shortcuts (Ctrl and Shift keys) to select, multi-select, and unselect any combination of control points on these curves.

  • You cannot add a point past the end points. To do this, you need to add a point before the end point, move the new point where the end point lies, then move the end point to a new location.

  • The creation plane for each free point is defined according to the current plane/compass orientation on the previous point. Therefore you can change creation planes within the same curve, by setting a new current plane/compass orientation on several points.

Available capabilities from the Dashboard, and/or specified through the FreeStyle Settings, are: datum creation, temporary analysis, auto detection (except for Snap on Control Point option), attenuation, and furtive display.