Algorithmic Arts has freeware Modular Synth Layout generators for Windows that provide modular synth enthusiasts another way to dream big.
According to the site, “These programs are for the modular synthesizer enthusiast, to help you dream the big dreams. They make it easy and quick to try out different module layouts by simple point and click, drag and drop. You can specify any case or rack set up, place your modules in it with instant graphic and module information feedback, and then rearrange modules or change case sizes however you like, as often as you like.”
Currently 7 synthesizers are supported, Analogue Systems, Blacet Research, Doepfer, Synthesizers.com, MOTM, and Modcan with Cynthia supported in the same program.
Algorithmic Arts also makes several software step-style sequencers that can be used with modular synths.