Question about VA?

[tee boy]

How are the wave forms generated in a digital va synth? I know that some digital synths use wavetables, but i figure this is different to using pure synthesis. What would be the most effective (and efficient) way to create the typical subtractive wav forms in a digital synth? How would you be able to model them on those of a real analgue synth?

My guess would be to use FFT to generate waveforms, then maybe some kind of convolution algorithm to model it on the real oscillator. Ofcourse, this is just shear speculation, cuz in reality i dont have the foggyist! Just curious...