An approach to concurrent type and dimensional synthesis of planar mechanisms is presented. Using graph-theoretic enumeration of mechanisms and determination of loops, automatic loop closure equations are generated. Using constrained optimization routines based on descent methods, and given an appropriate goal function, optimal mechanism designs can be determined. These are not limited to traditional problems such as rigid-body guidance and path generation, but can be more flexibly expressed according to designer needs. This method can be effective at finding mechanism solutions when topology has not been determined a priori and may also be extensible to synthesis of spatial mechanisms. This paper presents the data flow and algorithm outline, simulation results, and examples of nonstandard synthesis problems solvable with this method.