The two original surfaces are on the left, drawn in red and blue. The right edge of the red surface abuts the left edge of the blue surface, but the points on the edges are mismatched.
In the middle picture, the same blue surface is shown, but only the boundary loop is shown for the red surface. Points along the right edge of the red surface boundary loop have been redistributed and/or added to coincide with the points on the left edge of the blue surface.
In the picture on the right, the same blue surface is again shown, and a new unstructured grid has been created in the red surface with points on the right edge that coincide with the points on the left edge of the blue surface.
Last updated 19 July 2007