c# - WPF camera animation issue -

i have 3d model in wpf , im trying make animation makes camera go around model. have following code:

public mainwindow()         {             initializecomponent();             registername("thiswindow", this);         }  private model3dgroup mainmodel3dgroup = new model3dgroup(); private perspectivecamera thecamera; private double cameraphi = math.pi / 6.0; private double cameratheta = math.pi / 6.0; private double camerar = 35.0;  private storyboard storyboard = new storyboard(); private dependencyproperty cameraphiproperty = dependencyproperty.register("cameraphiproperty", typeof(double), typeof(mainwindow));  private void window_loaded(object sender, routedeventargs e)     {         // define model, lights , everthing         animations();     } private void rotatearoundtower()     {         doubleanimation animation = new doubleanimation();         animation.from = 0.0;         animation.to = 360.0;         animation.duration = new duration(timespan.fromseconds(10));         animation.repeatbehavior = repeatbehavior.forever;          storyboard.children.add(animation);         storyboard.settargetname(animation, "thiswindow");          storyboard.settargetproperty(animation, new propertypath(cameraphiproperty));     }  private void positioncamera()     {         // translates cameraphi , cameratheta coordinates , positions camera accordingly     } 

everything have of animation pieced found on msdn, seems me problem animation changes dependencyproperty cameraphiproperty object, , positioncamera never called. how can pass value dependencyproperty cameraphi , call positioncamera? or there cleaner solution animating this?