In one of my other threads, I asked obiwannabe for some waveguide examples, and he posted the patch from here. So I studied Kim's patches and didn't really understand them, because I had quite a bit to learn about waveguides.

So I read a bunch of stuff on Julius O. Smith's site, and built my own waveguide guitar based on my understanding of the concepts he presents. I haven't gotten too deeply into the math, but I created a guitar where the string models have a delay for each axis with energy transfer between the axes (and through the body). I have no idea how correct this is, but it sounds OK:

http://www.lubbertdas.org/waveguideguitar.pd
http://www.lubbertdas.org/waveguideguitardemo.mp3 (playing an excerpt from "A Quick One While He's Away," with some percussion accompaniment)

The patch was made in Pd-extended, and includes [packel] from Zexy in the strum message interpreter. It's also kind of CPU-expensive. I think I read that the body response can be commuted to the impulse or something, but I don't know if that applies in this situation because these recirculating delay systems hurt my brain.

It really sounds OK! Thanks for sharing!

And here's a monophonic bass built according to the same principles (scroll down to the bottom of the page).