Boundary-Constraint Meshing Based on Paving Method
This paper would modify thepaving method of Blacker and Stephenson  to generate boundary-constraint quad-mesh for arbitrary plane geometry. The basic idea for the present method is to classify the initial boundaries into closed borders and open borders.The closed borders aredescribed in a manner just the same as the paving method while the open borders areheuristically modeled as cracks with zero-width.And then the two kinds of borders aredelicatelyconnected each other to generate a new kind of boundary, named generalized closed boundary. Based on the newboundaries, the paving methodin Ref.  is adopted and modified slightly to generate quadrilateral elements by layering the geometry from the boundary toward the interior. And finally some meshing examples would be presented to illustrate the availability and power of the modified paving method.
Bale V. Reddy, Shishir Kumar Sahu, A. Kandasamy and Manuel de La Sen
J. Duan et al., "Boundary-Constraint Meshing Based on Paving Method", Applied Mechanics and Materials, Vol. 627, pp. 262-267, 2014