About getCOMAcceleration

Hi, all.
I tried the getCOMAcceleration function and has some questions.
I first add some forces to the skeleton, then I expect to get a non-zero COM acceleration. Indeed it returned with an acceleration vector. Then I step() the simulator. After that, I think the COM acceleration should be 0 as I already step() that and no new forces are added. However, I still get a non-zero vector.

This makes me guess that the getCOMAcceleration actually returns the acceleration before the ‘step()’ happens.

I wonder what’s the internal data update scheme and what’s the actual state of the data, when i use those get**() functions.

I just think it’s probably that any forces applied on the skeleton before step() will not cause a update of the data. Only when a step() is executed, all the data will be updated and the get**() funtion returns the effect of actions before ‘step()’?