Then I am missing something which needs to be save and restored.
I have a unit test which creates a simulation of 8 bodies connected by joints (similar to rag doll example with different joints).
I create an run a simultion with a number of steps.
Save the current state of the simulation.
Start a collection of stats about the collections locations and velocity.
Run for a number of additional steps.
Snap shot the stats.
Restart the simulation using save state.
Start a collection of stats on this new collection of locations and velocity.
Run for same number of additional steps.
Compare 2 sets of stats. When I compare these number they are different by about 0.2%.
The information I am saving is current location and velocity with angular components of each body.
I would think that I could have restored the system incorrectly, but until just recently I was using a different physics engine (physics2d) but I decide to port to Farseer. This is the last test to resolve before I am done with the port.
This test existed in the previous incarnation and I would get the exact same results, but not with Farseer.
Any ideas of what I am not saving and restoring?
Any help would save me alot of time to look at every possibility.