Split, Swap, Combine Elements

Use the Edit: Split tool to split quad elements and edges, combine tria elements, and swap element edges. Second order 2D and 3D elements are also supported.

The Edit tools work for tessellated geometry. If the input is b-spline geometry, first convert to discrete geometry using the Convert tool.
  1. From the Discrete ribbon, click the Edit > Split tool.


    Figure 1.
    Elements are colored according to how well they adhere to the pre-set quality requirements defined in the criteria file.
  2. Optional: On the guide bar, click to to define the options used to edit elements.
  3. Select an element issue type from the guide bar.
    Quality
    Checks for quality as defined in quality criteria.
    Intersections
    Checks for intersecting elements.
    Face angles
    Checks for folded or sharp angle elements.
  4. Optional: Find all elements at or below a certain quality level.
    1. Click Find on the guide bar.
    2. Increase or decrease the number of layers around patches of failed elements by clicking or on the guide bar.
    3. Review the next or previous patch of failed elements by clicking or on the guide bar.
  5. Select a split method from the guide bar drop-down menu.
    Option Description
    Quality
    • Split an element or element edge by left-clicking.
    • Swap an element edge by holding Ctrl while left-clicking on an element or edge. Additional clicks will cycle through the possible edge positions.
    • Combine two tria elements by holding Shift while left-clicking on their shared edge.
    Graphical Lines
    1. Draw continuous single or multiple graphical split lines.
    2. Click Split.


    Figure 2.
    Plate
    1. On the guide bar, click to to define the options used to split elements.
    2. Select elements to split.
    3. Select plate method.
    4. Optional: In the microdialog, divide quad elements into trias based on the advanced split option selected.
      Shortest
      Split quad element into tria elements using the shortest possible diagonal.
      Aligned
      Align the diagonals of all the tria elements in the same direction.
      Unionjack
      Split quad elements into tria elements so their diagonals create a unionjack pattern.
      Largest angle
      Split quad elements into tria elements using the largest angle diagonal.
    5. Optional: Reverse the direction of the split.
    6. Click Split.


    Figure 3.
    Note: When you split elements at fillets or curved faces, the middle nodes are projected back to parent edges/surfaces by default upon splitting.


    Figure 4.
    Solid
    1. Select the elements to split.
    2. Select a method for splitting solid elements
      • Hexas: split into hexas.
      • Tetras: split into a minimal number of tetras.
      • Symmetric: split into symmetric sets of tetras suitable for CFD.
    3. Click Split.
    When you split elements whose nodes are associated to a surface, the new nodes created are also on the surface.

    All split operators work on both first and second order elements.
    Layer
    1. Select nodes to define the direction of split/combine/delete.

      Two subsequent node selections define a direction. You can select multiple node pairs simultaneously, but they should be neighboring nodes. You can use By Path in Advanced Selection to define multiple splits and works for split only.

    2. Select a layer method.
      • Split: split hex elements along edges. You can select options for biasing while splitting layers.
      • Combine: combine neighboring elements.
      • Delete: delete layers of elements.
      • Diagonal: split a single element along the diagonal.
    3. Optionally, select the Elements check box and select elements to split.
    4. Click .
    Combine
    1. Select the elements to split.
    2. Click Combine.
    Tip: You can toggle graphical previews from the options menu.