It is important to realize that patents apply to ideas and algorithms, not to actual implementations. It is best to avoid known patented algorithms, that that is easier said then done.
Bullet soft body is implemented using a mix of velocity and position based projection, similar to Thomas Jacobsen's method described in GDC 2001: Advanced Character Physics paper
, which in turn was influenced by Bart Barenbrug relaxation method
, see some related discussion in 2001 on the ODE mailing list
. Matthias Muller position based dynamics is very similar to the Jacobsen method, but as far I know the Jacobsen method is valid prior art covering the Bullet implementation.
I'm looking for a project and I thought I'd work on realtime shattering objects,
Contributions to Bullet are very welcome, but before accepting contributions we do some basic review to make sure it doesn't obviously violate patents. Do you have any idea what authoring tools to use for shattering/fracture?