Creating Junctions

This command is only available with the Generative Shape Optimizer or Automotive Body in White Templates product.

This task shows how to create junction surfaces between existing surfaces. These surfaces must have been created from contours (sketches, splines, and so forth) provided these are not closed.

Open the Junction1.CATPart document.

  1. Click Junction .

    The Junction Surface definition dialog box is displayed.
  2. Select two sections.

    These can be surface boundaries or contour lying on surfaces.
    Coupling curves on which the junction surface will be based are displayed between the two sections.
  3. Select another section.

    New coupling curves are now displayed.
    If the sections do not present the same number of vertices, the system automatically links the coupling curves to the sections retaining the maximum number of points.
    In our example, two sections present four vertices whereas the last one presents only three. The system found a solution by linking two curves to the same vertex on the last section.
    Use the Sections coupling combo list to specify if the coupling lines are to connect sections on their tangency discontinuity points (Tangency option) or on their tangency discontinuity and curvature discontinuity points (Curvature option).
  4. Click within the Coupling Point area then select a point on the section on which you wish to redefine a new passing point for the coupling curve.

  5. Click Preview to preview the junction surface:

    By default the coupling curves and the junction surface are tangent to the contour plane's normal.
  6. Select a section from the list and click the surface on which it lies to add it as a support surface to the section, and therefore define a tangency constraint. 

    The coupling curves are modified so as to be tangent to the selected surface.
    You can also specify a user-defined coupling curve rather than an automatic one, by clicking the Coupling Curve tab, then selecting another curve connecting two sections of the junction.
    This new coupling curve either replaces an automatic one, or results in a new computation of automatic coupling curves.
    Indeed, in the following example, the user-defined coupling curve lies across the automatic ones. These are therefore recomputed to comply with the new constraint: 
    Using automatic coupling curves only Recomputed automatic coupling curves when using a user-defined coupling curve (blue curve)
  7. Click OK to create the junction surface.

    The element (identified as is added to the specification tree.
    • You can select as many sections as you wish.
    • There is no specific selection order. You can select sections randomly and obtain the same result.
    • User-defined coupling curves must end on sections.
    • You cannot use a coupling point and a user-defined coupling curve ending on this coupling point.