anchor.diff:  :keywords: beginner, intro, physics, documentation, input, model, control
   
   
  -Do you remember the <<jme3/beginner/hello_collision#,Hello Collision>> tutorial where you made the model of a town solid and walked through it in a first-person perspective? Then you may remember that, for the simulation of physical forces, jME3 integrates the link:http://jbullet.advel.cz/[jBullet] library.
  -
  -Apart from making models “solid, the most common use cases for physics in 3D games are:
  +Do you remember the xref:beginner/hello_collision.adoc[Hello Collision] tutorial where you made the model of a town solid and walked through it in a first-person perspective? Then you may remember that, for the simulation of physical forces, jME3 integrates the link:http://jbullet.advel.cz/[jBullet] library.
  +
  +Apart from making models "`solid`", the most common use cases for physics in 3D games are:
   
   *  Driving vehicles with suspensions, tyre friction, ramp jumping, drifting – Example: car racers
   *  Rolling and bouncing balls – Example: pong, pool billiard, bowling
   *  Sliding and falling boxes – Example: Breakout, Arkanoid
   *  Exposing objects to forces and gravity – Example: spaceships or zero-g flight
  -*  Animating ragdolls – Example: “realistic character simulations
  +*  Animating ragdolls – Example: "`realistic`" character simulations
   *  Swinging pendulums, rope bridges, flexible chains, and much more…
   
   All these physical properties can be simulated in JME3. Let's have a look at a simulation of physical forces in this example where you shoot cannon balls at a brick wall.
  
positive.code: 
  Fill your scene with walls, bricks, and cannon balls. When do you begin to see a performance impact?
  
  Popular AAA games use a clever mix of physics, animation and prerendered graphics to give you the illusion of a real, “physical world. Think of your favorite video games and try to spot where and how the game designers trick you into believing that the whole scene is physical. For example, think of a building “breaking into 4-8 parts after an explosion. The pieces most likely fly on predefined (so called kinematic) paths and are only replaced by dynamic Spatials after they touch the ground… Now that you start to implement game physics yourself, look behind the curtain!
  
  Using physics everywhere in a game sounds like a cool idea, but it is easily overused. Although the physics nodes are put to “sleep when they are not moving, creating a world solely out of dynamic physics nodes will quickly bring you to the limits of your computer's capabilities.
  
  
  == Conclusion
  
negative.code: 
  == A Basic Physics Application
  
  In the previous tutorials, you used static Geometries (boxes, spheres, and models) that you placed in the scene. Depending on their translation, Geometries can "`float`" in mid-air and even overlap – they are not affected by "`gravity`" and have no physical mass. This tutorial shows how to add physical properties to Geometries.
  
  As always, start with a standard com.jme3.app.SimpleApplication. To activate physics, create a com.jme3.bullet.BulletAppState, and and attach it to the SimpleApplication's AppState manager.
  
  