title: XNA 4.0 - Rotate around own axis and around world centre
body: <p>I have planets rotating around Sun. Sun is in the middle.</p>
  
  <p>I want to make planets rotate around both the sun and their own axis.</p>
  
  <p>My rotation code is:</p>
  
  <pre><code> world_.SetValue(Matrix.CreateRotationZ(-(float)
                    ((gameTime.TotalGameTime.TotalSeconds % 100) * 2 * Math.PI / 100)));
  </code></pre>
  
  <p>It seemed to me as something easy to implement (since i can do that in OpenGL, Android etc) but for some reason im stuck...</p>