A general approach is presented for generating compliant mechanisms from a highly connected ground structure. The structure is modeled as a pin-jointed truss, and geometrical nonlinearity is considered. An optimization problem is formulated for minimizing the total structural volume under constraints on the displacement at the specified node, and stiffnesses at initial and final states. The design variables are cross-sectional areas and the nodal coordinates. It is shown in the numerical examples that several mechanisms can be naturally found as a result of optimization starting from randomly selected initial solutions.