Does your software synth contain samples from other instruments?
Are you really using a synthesizer?
Fathom was developed with the philosophy that to be called a synthesizer an instrument must be able to generate its own waveforms from first principles.
Fathom provides the tools necessary to realize virtually any waveform.
This includes a free-hand drawing tablet and exponential and Bezier curves.
The GUI supports wave editing as an art form with views that expand to fill the entire interface when they are selected.
Fathom is a great option if you use waveform libraries such as AKWF and Galbanum and want to make edits to the waveforms.