I would like to know , If part of our model has geometrical complexity , is it reasonable to use meshfree method for that area ? does it fasten or ease the analysis ? how to couple it with FEM ?
Below is the main reference that describes how you may do what you want.
Fernandez-Mendez, S. and A. Huerta (2004). Imposing essential boundary conditions in
mesh-free methods. Comput. Methods Appl. Mech. Engrg. 193, 1257–1275.
This technique of blending MLS (meshfree) shape functions into FEM shape functions has been implemented to enforce essential boundary conditions in the following paper
You can read the relevant sections and get the basic idea.