Three patches that implement some basic physical modeling with expr and fexpr~.

Ammortis.zip

thanks! it would be great to get something like springsound http://www.anckorage.com/spring-sound/ in pd. combining a few spring models in a chain can produce an enormous range of possibilities.

If you're interested by physical modeling, you can take a look on the pmpd external introduced by http://recherche.ircam.fr/equipes/repmus/SMC04/scm04actes/P47.pdf

Pardon my ignorance but I am confused as to what the two outputs are defined as for the expr function? (I sort of understand the first but need some clarification but for the second I am lost)

@mikkejos22 The [expr] family can contain more than one expression.
The object will start with "expr" "expr~" etc and then there is some work done.
A second expression can be added by a semi-colon separator....... the ; means "new line".
Then the left outlet will give the result for the first expression, and a new outlet will be added for the result of each subsequent expression.......
....... eg........