The perimeter of the mesh resulting from the triangulation process corresponds to the convex hull of the data points. This may result in some long thin triangles or "slivers" on the perimeter of the triangulated region.
There are several ways to select and delete long thin triangles. The "drag line" method for selecting elements was designed specifically for this purpose. Elements can be selected with a line by selecting the Select Elements tool, holding down the Control key, and dragging a line through all of the elements to be selected. The selected elements can then be deleted.
A display option can be set to display thin triangles by filling them in with a user-specified color. This aids in the identification and deletion of thin triangles. A triangle is defined as "thin" if it has an aspect ratio below a critical value. The critical aspect ratio can be set by selecting the Mesh | 2D Mesh Settings menu command.
Long thin triangles on the perimeter of the mesh can be automatically selected using the Select Thin Triangles item from the Mesh menu. The triangles on the outer boundary are checked first and if the aspect ratio of a triangle is less than a critical value, the triangle is selected and the triangles adjacent to the triangle are then checked. The process continues inward until none of the adjacent triangles violate the minimum aspect ratio.
Related Links:
Editing 2D Meshes