Creating Intersections

This task shows you how to create wireframe geometry by intersecting elements.

You can intersect:

  • wireframe elements
  • solid elements
  • surfaces

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.
 
  • Extend linear supports for intersection enables to extend the first, second or both elements. This option is especially useful if you work within an ordered geometrical set environment. In some confusing cases (for instance shallow angles), this option may give a more accurate result as it takes into account the geometry rather than the topology.
    Both options are unchecked by default.
    Here is an example with the option checked for both elements.

 
 
  • Extrapolate intersection on first element enables to perform an extrapolation on the first selected element, in the case of a surface-surface intersection. In all the other cases, the option will be grayed.
     
    Intersection with the Extrapolation option unchecked   Intersection with the Extrapolation option checked
 
  • 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 selecting 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.