In Bullet, we need to call a function to update the dynamic physics world so that the game world continues to progress. This is achieved by the stepSimulation()call. We provide three parameters, the delta time, maximum substeps, and a fixed time step. The following code will explain everything:

   world.stepSimulation(Gdx.graphics.getDeltaTime(), 5 , 1/60f);

Bullet will perform as many (but not more than the specified maximum) calculations using the specified 1/60f delta time, until it reaches the specified actual elapsed delta time. Obviously, it's very unlikely that the delta value is always exactly a multiple of 1/60f. In fact, it is possible in some cases that the value of delta is less than specified 1/60f, causing Bullet not to perform any calculations at all. Using this along with custom btMotionState will provide a smooth transition in our game.