CFX-Mesh contains two ways of removing short edges: Short Edge Removal and Virtual Edges. This section describes the differences between them.

Short Edge Removal removes all edges shorter than a certain length (which you specify) in the geometry. When the mesher sees a short edge which is to be removed, the behavior is as if the edge was collapsed to zero length: a single node is placed at one end of the edge and no other nodes are put on the edge at all. As a result, you can only merge short edges which are shorter than the local mesh length scale, or your resulting mesh will be badly distorted. There is no individual control over which edges should be regarded as short; all edges below the specified length scale will be removed.

The creation of a Virtual Edge is effectively a merger of two or more edges, creating a single, longer edge. The mesher will place nodes along the Virtual Edge with no regard for where the original edges were. There is no requirement that the merged edges are smaller than the mesh length scale. However, you can only merge edges which are shared between the same two faces of the geometry. You have individual control over which edges are merged and can create each Virtual Edge separately. In some circumstances Virtual Edges can also be created automatically; see Virtual Edges for more details.

Short Edge Removal and Virtual Edges can be used in the same mesh setup. Where the setup contains both, Virtual Edges take precedence, i.e., Virtual Edges are created first, and then Short Edge Removal removes any remaining edges of a length shorter than the given length scale.

In general, where it is possible, it is recommended that you remove short edges by using Virtual Edges rather than Short Edge Removal. This approach results in greater consistency with other features of CFX-Mesh.

Some examples are shown in the table below.

Example	Geometry	Mesh with short edge	Mesh without short edge
1
	In this example, the short edge to be eliminated can be removed by using Short Edge Removal, provided that the mesh length scale is large enough and there are no shorter edges elsewhere in the geometry that you need to keep. In this example the mesh length scale is only a few times longer than the length of the short edge and so there is a very slight distortion in the mesh where the node from one end of the edge has been collapsed onto the node at the other end of the edge. The short edge cannot be removed using Virtual Edges because there is no edge shared between the same two faces that it can be merged with.
2
	In this example there is a whole series of short edges to be removed. Short Edge Removal cannot be used because the entire length of the series of edges would be collapsed and the distortion would be too large. However, the series of short edges can be merged into one Virtual Edge.
3
	In this example, either Short Edge Removal could be used or the short edge could be merged with its neighbor to its right to make Virtual Edge. The decision on which method to use would depend on whether you had other short edges you wanted to remove and whether you needed the individual control that you get by using Virtual Edges. The resulting mesh produced by the two methods is slightly different. The top mesh, produced by Short Edge Removal, is very slightly distorted since the mesh length scale is not much greater than the length of the short edge. The bottom mesh is produced by the Virtual Edge method.