If topological errors are found in the file, the surface mesh enhancer may display messages directing you to other files, such as:
****ERROR: Errors in input (Holes=Purple, Multiple=Red) See error. esd.
Also, a file named filename.erm may be created. The file contains the input file after all quads have been converted into triangles and any dangling and duplicate triangles have been removed. Dangling triangles have only one edge connected to the rest of the model.
Edges that are connected to only one triangle are shown as purple lines (layer 6). Edges that are connected to more than two triangles are shown as red lines (layer 2). To correct the topological problems, you can rename the filename.erm file to an extension .esd and use 
Open command to view the file. (Set the Files of Type to Autodesk Simulation Superdraw III (*.esd).)
If the file is topologically correct but the surface mesh enhancer cannot complete the mesh, it generates a fatal error message and an filename.erm file. This file will include green lines for the elements that have been completed, blue lines showing the advancing front at which the surface mesh enhancer is currently creating elements and usually red lines that indicate the problem area.
Most of the surface mesh enhancer's meshing problems are a result of the mesh size being too large and are corrected by decreasing the mesh size. For these cases, there is not much value in looking at the filename.erm file as reducing the mesh size will correct the problem.
If reducing the mesh size does not correct the problem, you can examine the filename.erm files for several different mesh sizes. If the errors (red lines and/or points) occur in the same physical region, it may be useful to simplify the mesh in that region. Before trying to correct the mesh yourself, generate a feat.esd file and look at the region near the error (you can delete all but the red lines in the filename.erm file, save it under another name and then merge it over the feat.esd file to identify the problem region in the feat.esd file). If the problem region has skinny feature triangles, try increasing the -pc value to remove some of the feature triangles.
If the feat.esd file doesn't indicate the problem or if increasing the Clean Initial Triangles value doesn't correct the problem and you are an experienced hand-model builder, try to simplify the mesh in the region of the problem. There is difficulty in using a wire representation of a three-dimensional mesh on a two-dimensional screen. Careful use of the layer command can help in isolating the surface of interest. This is not always a fruitful approach because it is difficult to do and there is a good chance an .stl file with one problem region may have other problem regions. But if you can fix one or two regions and get the surface mesh enhancer to create your mesh, this is usually faster than generating the full mesh by hand.