Merging Subdivision Surfaces  

This task shows you how to merge two subdivisions at their open edges.

Open the MergeSubdivisionSurfaces.CATPart document.

  1. Click Merge in the Styling Surfaces toolbar.
    You can also access this command by pressing ALT+SHIFT+W.

  2. Select Start Surface from the specification tree. The first surface selected is the surface that is going to be modified.

  3. Select Surface to Add 1. This surface will be added to the first surface.  

    A Tools Palette is displayed.
    • Merge Surface Selection : Allows you to reselect the surfaces to be merged.
    • Merge : The two surfaces are merged to create the merged edge at the middle of the selected edges. The number of selected edges on both the surfaces must be same.
    • Join : The two surfaces do not move and are joined by one face. The number of selected edges on both the surfaces must be same.
    • Extrude : The two surfaces are joined by faces. The number of selected edges on both the surfaces must be same.

    In case of different number of edges between the two surfaces, only one edge is merged, joined or extruded depending on your selection.

    • Apply (Enter) : Validates the previewed result of subdivision fusion. When the modification is not possible, the Apply (Enter) icon is not active (grayed out). 

    By default a result is previewed where the free edges used to junction the two surfaces are automatically selected. The automatic selection selects the nearest two free edges.
    In this case, Merge option is previewed as seen.

  4. Click Join. The result is as seen.
  5. Click Extrude. The result is as seen.
  6. Select different set of free edges.
  7. Click Apply (Enter) to validate the selection.

    After validation, the selection of a new surface to be added is automatically activated.

  8. Select the another subdivision surface Surface to Add 2 to merge it with the existing merged subdivision surface.
  9. Select subdivisions with different number of free edges to create a Join.
    You can see that only one edge is joined between both surfaces.

    To merge, join or extrude the remain edges you could use the fill command.
  • Two subdivision surfaces can be merged only at their open edges as the junction is made by this free edge side.
  • Undo and Redo commands are not available.