One of the problems with the preceding technique is that feathering can occur due to the gaps between consecutive edge quads:

The preceding diagram shows the feathering of a silhouette edge. The gaps between the polygons can be filled with triangles, but in our example, we simply extend the length of each quad to fill in the gap. This can, of course, cause artifacts if the quads are extended too far, but in practice they haven't been very distracting in my experience.

A second issue is related to depth testing. If an edge polygon extends into another area of the mesh, it can be clipped due to the depth test. The following is an example:

The edge polygon should extend vertically throughout the middle of the preceding image, but is clipped because it falls behind the part of the mesh that is nearby. This issue can be solved by using custom depth testing when rendering the silhouette edges. Refer to Philip Rideout's blog post mentioned earlier for details on this technique. It may also be possible to turn depth testing off when rendering the edges, being careful not to render any edges from the opposite side of the model.