Breaking Curves

This task shows you how to break curves. Curves can be broken by any combination of points, curves, planes and surfaces. See also Breaking Surfaces.
Available functionalities from the Dashboard are:
Open the FreeStyle_Part_40.CATPart document.

  1. Click the Break Surface or Curve icon:

    The Break dialog box and the Tools Palette appear.

  2. Select the Break Curves option if needed:

    The Break dialog box content has been modified according to the selected type.
    The Break dialog box displays the following information:

    • Break Type:

      • Break Curves: breaks the curves.

      • Break Surfaces: breaks the surfaces.

    • Selection

      • Elements: defines the set of curves or surfaces to be cut.

      • Limitation: defines the set of limiting elements such as points, curves, planes or surfaces.

      • Break Both: breaks elements to be cut and limiting elements by each other.

    • Invert Selection: You can use this option to invert (move) the selection from the current state to the other state depending on the allowed selection type of the other state. For example, if, by mistake, you select three surfaces and one curve in Limitation state with Break Surface as the break type, and then just press the Invert Selection option to move all the three surfaces to the Elements state provided, the current state is Limitation. With this option, all the elements in the current state are moved to the other state. Note that the curve will not be moved to the Elements state, as selection of 1D elements is not allowed in the Elements state with the break type Break Surface. So the curve will remain in the Limitation state.

    • Disassemble: You can use this option to disassemble multi cell/domain bodies into mono cell bodies. When this option is unchecked, and you select a multi cell/domain body as Elements input and break it using a curve such that only one cell/domain is broken by this curve, the result should contain only two elements. But when this option is checked, the multi cell/domain results are disassembled into mono cell bodies.

    • Fragments: Fragments an input curve(s) or surface(s) without selecting the Limitation inputs set. If you select a curve(s) or surface(s) in the Elements input set and checks the Fragment option, the Limitation input selector would be inactive. Also, all the other options will be inactive. Now when you press the Apply button the curve(s) or surface(s) will be broken by its segment boundaries. Report shows the status for the cutting elements. In this option as there is no cutting element, report will always display “No computation done”.
    • Break in to equal number: Only available in case of Break Curves break type. You can use this option to break an input curve/s into ‘x’ equal parts without selecting the Limitation inputs set. If you select a curve in the Elements input set and checks this option, the Limitation input selector will be inactive. Also, all the other options except relimitation options will be inactive. You have to specify the number parts you want to break each curve into, through the spinner provided. When you press the Apply button each curve will be broken into ‘x’ equal parts. Report shows the status for the cutting elements. In this option as there is no cutting element, report will always display “No computation done”.
    • Keep order with surface trim: In case of surface trim option, the maximum deviation, if any, between the original and the resulting outputs are shown in the dialog box as well as in the 3D. The command is migrated to the new common architecture for the Freestyle and Automotive Class A.
    • Trap Selection:  If you drag a trap in the model, all included elements will become selected. If no modifier was pressed, the current selection is emptied and only the included elements in the trap become selected. If CTRL is pressed while creating the trap, the included elements are added to the current selection.
    • Stack command under Limitation:
      • When the Curves option is selected, the Limitation input editor is stacked with the following commands:
        • Create Point
        • Create Midpoint
        • Create Plane
      • When Surfaces option is selected, the Limitation input is stacked with the following commands:
        • Create Plane
        • Create Isoparameter
        • Create 3D Curve

    • Trim Type:

      • Edge Trim: curves are topologically relimited and the control points of the initial curves are kept.

      • Curve Trim: curves are geometrically relimited and the control points of the resulting curves are kept.

    • Order

      • U: defines the U order.
        Available only with Break Surfaces and Surface Trim options.
        The U and V order maximum values are set with the Order setting option of the FreeStyle settings.

      • V: defines the V order.
        Available only with Break Surfaces and Surface Trim options.
        The U and V order maximum values are set with the Order setting option of the FreeStyle settings.

    • Projection: By default the points that do not lie on the trimmed elements will not be projected onto the trimming elements.

      • Along Compass: projects along the compass direction.

      • Along Normal: projects along the normal direction.

      • Along Viewing Direction: projects along the viewing direction.

    • Extrapolation:

      • Tangential Extrapolation: extrapolates along the tangent direction.
        Available only with Break Surfaces option.

      • Curvature Extrapolation: extrapolates along the curvature direction.
        Available only with Break Surfaces option.

    • Report: displays a status about cutting elements:

      • Cutting elements that can be used for the Break (marked by a green tip). When you click on the text, the corresponding curve is highlighted in green in the 3D geometry.

      • Cutting elements that cannot be used for the Break (marked by the condition to be applied so that they can be used: projection, etc). When you click on the text, the corresponding curve is highlighted in red in the 3D geometry.

        • When there is no selection of cutting elements, an error message is issued and the Break Report panel informs you that no element is selected.

        • When a red cross is displayed, it means that the problem cannot be managed by the application.

    • Max deviation: displays the maximal deviation between original surface and the resultant surface in the dialog box and on the geometry. This is available only with Break Curves and Trim Surface options.

  3. Select the curve.

  4. Select the Cutting field in the Break dialog box and select the surface and the curve as shown.

  5. Click the Limitation List icon:

    The Limitation List dialog box appears. You can manage inside this dialog box the limiting elements: remove or replace.

  6. Click Close in the Limitation List dialog box.

  7. Click Apply in the Break dialog box.

    Only the white elements are trimmed. By default, only one trimmed element is kept (plain line) other not (dashed line).

  8. Click the curve segment to be kept: it appears with a plain line in the 3D geometry.

  9. Right-click any relimited element to display the following contextual menu.

    • Keep all: all parts of the all curves are kept.
    • Keep all but this: all parts of all curves are kept except the selected one.
    • Remove all but this: all parts of all curves are removed except the selected one.
    To keep, or do not keep, some elements press the Ctrl key and click them.

  1. Click the Along Compass option:

  2. Click Apply in the Break dialog box.

    Elements that do not lie on the trimmed elements will be projected (pseudo-intersections) onto the trimming elements according to the compass direction.

  3. Click OK in the Break dialog box.