Combining Quadrilateral and Triangular Meshing Using the Advancing Front Approach

A fully automatic mesher has been developed which is capable of generating both quadrilateral and triangular elements in 2-D and on surfaces using the advancing front algorithm. This allows the formation of meshes which range from being all-quad or nearly all-quad down to all-triangular. In mixed-element meshes, the number of tri elements present is dictated by the maximum allowable level of quad distortion spec-iied by the user. Triangular elements are added during localized remeshing and only after attempts to add acceptable quadrilateral elements at every segment of the remaining mesh area have failed. In this way, the user is assured that unacceptably distorted quadrilaterals are avoided and the number of triangular elements is kept to a minimum. Mesh enhancement techniques further eliminate triangular elements and improve element quality.