Creating Intersections

This task shows you how to create wireframe geometry by intersecting elements and how to regenerate deleted intersection outputs.

You can intersect:

  • wireframe elements
  • solid elements
  • surfaces
Create a Wireframe Geometry by Intersecting Elements

Open the Intersection1.CATPart document.

  1. Click Intersection .

    The Intersection Definition dialog box appears as well as the Tools Palette.
    For further information about the Tools Palette, refer to Selecting Using Selection Traps in the CATIA Infrastructure User's Guide.

  2. Select the two elements to be intersected.

    The intersection is displayed.
    Multi-selection is available on the first and second selection, meaning that you can select several elements to be intersected as well as several intersecting elements. For instance you can select a whole geometrical set.
  3. Choose the type of intersection to be displayed.

    • a Curve (when intersecting two curves):
     
    • Points (when intersecting two curves):
     
    • a Contour: when intersecting a solid element with a surface :
     
    • a Face: when intersecting a solid element with a surface (we increased the transparency degree on the pad and surface):
  4. Click OK to create the intersection element.

    This element (identified as Intersect.xxx) is added to the specification tree.
     
    The above example shows the line resulting
    from the intersection of a plane and a surface
      The above example shows the curve resulting
    from the intersection of two surfaces

Additional Parameters

Several options can be defined to improve the preciseness of the intersection.

Open the Intersection2.CATPart document.Extrapolation Options
These options are only available for surface-surface intersections.
You can extrapolate the intersection result.

 
  • Intersect non coplanar line segments enables to perform an intersection on two non-intersecting lines.
    When selecting this option, both Extend linear supports for intersection options are selected too.
     
    Intersection between the light green line and the blue line: the intersection point is calculated after the blue line is extrapolated Intersection between the pink line and the blue line: the intersection is calculated as the mid-point of minimum distance between the two lines
 
The following capabilities are available: Stacking Commands and Selecting Using Multi-Output.
  • If you select a body or a hybrid body containing both solid and wireframe elements as input, only the solid elements are taken into account to compute the intersection.
  • Avoid using input elements which are tangent to each other since this may result in geometric instabilities in the tangency zone.
  • If the intersection stops at an edge and providing the edge can be merged with the intersecting element (if the distance is less than 0.1mm), then it is projected onto the intersecting element. The projection is integrated to the intersection result.
Regenerate Deleted Intersection Outputs
You can regenerate the deleted intersection outputs at any stage of the design by editing the multi-output feature. This is useful when the intersection is cancelled due to design modifications and you want to recover the earlier outputs.
Open a CATPart document where at least one of the intersection output is deleted.
  1. Double-click the multi-output feature in the specification tree.
    The Intersection Definition dialog box appears.
  2. Select the Regenerate all deleted features check box.
    • The Regenerate all deleted features check box appears whenever the multi-output feature has fewer children compared to the result of number of features in the First Element box multiplied by the number of features in the Second Element box. If there are no additional intersections, selecting the Regenerate all deleted features check box will not change the number of children.
    • Depending on your part, even if the above condition is fulfilled, new intersection outputs are generated only if they were present in the design before.
     
  3. Optional: Click Preview.
    All intersection features are displayed in the work area. In the specification tree view, they are aggregated under the multi-output node.
      The outputs are inserted after the last element in the node and are numbered accordingly, instead of being inserted at their original positions. 
  4. Click OK.
    The intersection outputs are regenerated.
    You can undo the regeneration operation to go back to the previous design stage.