anchor.diff:  
   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.
  +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
  
positive.code: image::beginner/beginner-physics.png[beginner-physics.png,360,291,align="center"]
  
  
  
  [TIP]
  ====
  To use the example assets in a new jMonkeyEngine SDK project, right-click your project, select “Properties, go to “Libraries, press “Add Library and add the “jme3-test-data library.
  ====
  
  
  
  == Sample Code
  
  Thanks to double1984 for contributing this fun sample!
  
  [source,java]
  ----
  
negative.code: 
  === Geometries
  
  In this "`shoot`" at the wall example, you use Geometries such as cannon balls and bricks. Geometries contain meshes, such as Shapes. Let's create and initialize some Shapes: Boxes and Spheres.
  
  [source,java]
  ----
  