Selecting Control Points

This task explains how to select control points according to the different selection options.
These options define selection filters and other selection associativities:
  • Manipulation filters
    • Points only: allows you to select control points selecting points only.
    • Mesh only: allows you to select control points selecting their mesh lines only.
    • Points and mesh: allows you to select control points either selecting points or their mesh lines.
  • Select all points: selects all the points of the control points mesh. This command is also available from the mesh lines and control points contextual menu.
  • Deselect all points: unselects all the points of the control points mesh.
  • Display Inflections: displays arrows at the control points representing their normal vectors and deduces the inflection at the control point locations. These arrows are displayed when the surface is not locally planar at the considered control points and when the control points are connected to three mesh lines at least.
    This option is P2-only.
  • Display deviation: displays the maximal deviation location and value in 3D, the deviation value is also displayed at the bottom of the dialog box.

When approaching the control points mesh, the cursor changes from the arrow representation to a cross representation and the nearest mesh line or control point is automatically pre-selected. The cursor representation can be customized from the Tools Options settings.

Shift and Ctrl keys allow you to add mesh lines or control points to the selection.
Open the FreeStyle_Part_38.CATPart document.

  1. Click the Control Points icon:
    The Control Points dialog box appears.

  2. Select Surface.1

    Control points and the mesh are displayed on the surface.

  3. Click the Elements List icon: 
    The Elements dialog box appears and displays the list of selected elements.

  4. Click Close in the Elements dialog box.

  5. Click the Normal to compass icon if not already selected:

  6. Click the Points only icon if not already selected:

    Approaching the cursor close to the mesh allows you to select control points only.

  7. Click the point or click close to it to select it.

  8. Click the Mesh only icon from the Options frame:

    Approaching the cursor close to the mesh allows you to select mesh lines only.

  9. Click the mesh line or click close to it to select itself and its control points.

  10. Click the Points and mesh icon from the Options frame:

    This option combines the two previous selection filters.

    Keep in mind that when using Points and mesh:

    • If you select a mesh line, all its control points are selected too.
    • If you have to select the point only, you have to select it itself.
    Dashboard Options allow you to facilitate the control points manipulation:
    •  Manipulators snap allows you to snap:
      • A control points onto a target point, which can be:
        • A vertex.
        • A control point.
        • A position on a curve.
        • A position on a surface.

        Furthermore, only the following options can refined the selection:

        •  Snap On Vertex: to detect the closest corner of the selected element.
        •  Snap On Edge: to detect the closest border (edge) of the selected element.
      • A mesh line onto another mesh line of same dimension.
    • Manipulator mode:
      You can change the current mode type to the next by clicking the icon.
      • Dynamic mode: the control point manipulator follows the mouse cursor.
      • Step mode: the control point manipulator snaps to a relative grid step,
        • The grid step is defined in a combo of the Dashboard toolbar.
    • Manipulator position:
      • 3D Manipulator: displays the distance between the current position of the manipulator and the its latest one.
      • Local Coordinates: displays the local coordinates of the current position of the manipulator from its latest one, according to the part axis system.
      • Absolute Coordinates: displays the absolute coordinates of the current position of the manipulator, according to the part axis system.

  11. Select both Surface.1 and Surface.2.

    Control points and the mesh are displayed on both surfaces.

  12. Click the Manipulators Snap icon from the Dashboard toolbar:

  13. Select the first control point.

    Note that mesh representations have been simplified.

  14. Select the second control point.

    The first control point has been snapped onto the second control point.

  15. Click OK to validate modifications and close the dialog box.

 Separation of selection / manipulation states:
  Two very different states are provided in the command: a selection and a manipulation states.
  1. Selection state: You can only select some geometries to be manipulated, but cannot manipulate them. The mesh will be displayed on those latter, but cannot be picked.
  2. Manipulation State: In the second one, the selected elements can be manipulated. No geometry can be selected. Click in the empty space should not de-selected the selected geometries.

New selection of elements
 
  1. When you click on the element to be manipulated (with no modifier key), the command automatically jumps to the manipulation state, in order to enable the manipulation of the element.
  2. When the you click on the element to be manipulated with CTRL pressed, the command remains in the selection state, so that multi-selection is allowed.
  3. When the you click in the empty space to de-select all the geometries, the command remains in the selection state, as no selection is done.
  4. When the you click on the bag icon near the selector and opens the multi-selection dialog, geometries can be selected and/or de-selected with or without CTRL key pressed. As soon as you close the multi-selection dialog, the command automatically jumps to the manipulation state.
  5. F8 shortcut can be used to quickly switch from one state to the other (unless the multi-selection dialog is opened).

New selection trap of control points
  In the manipulation state, the control points can be selected using a rectangular trap selection. Using CTRL modifier, control points can be added/removed to/from the current selection.

The settings for the Mesh are mentioned under the topic Manipulators > New Setting for the Mesh.

Edge selection and manipulation
  In V5R17, edges can be selected to relimit the face of the geometry. This behavior already existed in V5R14, but was not yet implemented in the new version of the control point command. This is now done. Note that algorithms were completely re-written, so that some modifications may appear in the result between V5R14 and V5R17.

When a topological issue is detected, a dialog box pops up with a warning. This was not the case in V5R14.