public void setMaxSubSteps(int steps) {
        maxSubSteps = steps;
    }
Sets the maximum amount of extra steps that will be used to step the physics
when the fps is below the physics fps. Doing this maintains determinism in physics.
For example a maximum number of 2 can compensate for frame rates as low as 30fps
when the physics has the default accuracy of 60 fps. Note that setting this
value too high can make the physics drive down its own fps in case it's overloaded.
@param steps The maximum number of extra steps, default is 4.
jme3-jbullet/src/main/java/com/jme3/bullet/PhysicsSpace.java