Fixing Overlapping Elements

Import a model into MPI/Synergy, then select Mesh > Mesh Statistics. Look under Intersection Details for information about Element Intersections and Fully Overlapping Elements. These are defects in the mesh that you will need to fix before running an analysis.

Select Mesh > Mesh Tools to access tools that will help you fix the defects. First, try the Auto fix tool, which automatically tries to fix overlaps and intersections. Don't worry about the result, because the tool reports Aspect Ratio before and after - this will change only if the fixed defect happens to be related to the minimum or maximum aspect ratio. Check Mesh Statistics again to see if Auto fix solved your element problems.

If Auto fix did not fix all the defects, go back to Mesh Tools and select Global Merge. This tool merges nodes within a specified tolerance. Be careful if you leave the Preserve Fusion checkbox option blank! When checked (turned on), this option prevents nodes from being merged if this would result in the removal of a side of a triangle.

Your next option is to display the overlapping elements and manually fix the mesh. To display these elements, select Mesh > Overlapping Elements. On the dialog that appears, you can select to display Overlaps, Intersections or both. Be sure to check the Place Results in Diagnostic Layer option.

Deselect all layers, so that only the Diagnostic Results layer is visible. Clicking on the Diagnostic Results layer to highlight it, then select the Expand button. The Expand button grows the mesh around the highlighted layer by a user-defined level, in this case one. This feature is very useful to see what elements need to be fixed and the area around them.       Enlarge Next zoom in on one particular area and use the center icon to center the view for ease of rotation. There are many ways to fix overlaps and intersections. In this example, the problem element is protruding through other mesh elements at a corner. We can select and delete this element using Mesh Tools > Delete or simply by using the select icon to select the element and clicking the Delete key on the keyboard.

TIP: To speed up the mesh editing process, turn the mesh diagnostics window off before using any Mesh Tools or deleting elements. To do this, select Mesh > Show Diagnostic or click in the MPI/Synergy graphics window and click Ctrl + D. After the editing action is complete, you can turn the diagnostic window on again by repeating the process.

Enlarge   Enlarge   Enlarge

Another common way to fix overlaps is to merge nodes. This is also accomplished using the Mesh Tools menu. Simply select the node you want to merge to and then the node you want to be merged.