1. A computer implemented method for implementing an electronic design, the method comprising: using at least one processor that is configured or programmed for performing a process, the process comprising: identifying or generating a soft design model corresponding to a design block, wherein the soft design model is configured with a flexible shape and a flexible pin location, the design block comprises the soft design model, and the soft design model comprises an area specification for the soft design model, in which the area specification comprises an area of the soft design model; performing placement and routing for the electronic design, wherein the soft design model is included in a layout for the electronic design; configuring one or more shape parameters for the soft design model; and analyzing the layout as to whether design goals are met.