Question

There was some similar threads, but I didn’t find solution of my problem. It’s my first post here.
Here’s the thing:

Viewport3D viewPort3D;

GeometryModel3D geometryModel = new GeometryModel3D();  
Transform3DGroup transform3DGroup = new Transform3DGroup();

...

// Rotation
RotateTransform3D rotateTransform3D = new RotateTransform3D();   
AxisAngleRotation3D axisAngleRotation3d = new AxisAngleRotation3D();  
axisAngleRotation3d.Axis = new Vector3D(0, 1, 0);  
axisAngleRotation3d.Angle = angle;  
rotateTransform3D.Rotation = axisAngleRotation3d;  
transform3DGroup.Children.Add(rotateTransform3D);  

// Translation  
TranslateTransform3D translateTransform3D = new TranslateTransform3D();  
translateTransform3D.OffsetX = offsetX;
transform3DGroup.Children.Add(translateTransform3D);  

// Adding transforms  
geometryModel.Transform = transform3DGroup;  

Model3DGroup model3DGroup = new Model3DGroup();
model3DGroup.Children.Add( image.getGeometryModel3D() );

modelVisual3D.Content = model3DGroup;
viewPort3D.Children.Add( modelVisual3D );

And now I want to make translation using storyboard (because later I want to add also rotating to that storyboard):

Storyboard s = new Storyboard();

Transform3DGroup transform3DGroup = model3DGroup.Children.ElementAt(current).Transform as Transform3DGroup;

for (int j = 0; j < transform3DGroup.Children.Count; ++j)
{
   if (transform3DGroup.Children.ElementAt(j) is TranslateTransform3D)
   {
      TranslateTransform3D translation = transform3DGroup.Children.ElementAt(j) as TranslateTransform3D;

      DoubleAnimation doubleAnimation = new DoubleAnimation();
      doubleAnimation.From = 0;
      doubleAnimation.To = 2;
      doubleAnimation.Duration = new Duration(TimeSpan.FromSeconds(1));
      doubleAnimation.AutoReverse = true;
      doubleAnimation.RepeatBehavior = RepeatBehavior.Forever;

      s.Children.Add(doubleAnimation);
      s.Duration = new Duration(TimeSpan.FromSeconds(1));

      Storyboard.SetTarget(doubleAnimation, model3DGroup.Children.ElementAt(current));
      Storyboard.SetTargetProperty(doubleAnimation, new PropertyPath("(Model3D.Transform).(Transform3DGroup.Children)[1].(TranslateTransform3D.OffsetX)"));

      s.Begin(); // Exception during the execution.
   }
}

Exception in the last line:

‘[Unknown]’ property value in the path
‘(Model3D.Transform).(Transform3DGroup.Children)[1].(TranslateTransform3D.OffsetX)’
points to immutable instance of
‘System.Windows.Media.Media3D.TranslateTransform3D’.

I took PropertyPath similar to the path generated in blend 4.

Thank you for any help.

Answer 1

I think because translate tranform 3d is an immutable instance it has to be indicated that it should be mutable while rendering / translation is taking place.

I guess

1. We can supply x:Name to that immutable TranslateTransform3D object, to make it mutable.

2. Bind to its property than to animate it.

E.g. in your case

        NameScope.SetNameScope(this, new NameScope());
        this.RegisterName("AxisRotation", MyAxisRotation3DObject.Rotation);
        this.RegisterName("TranslateTransformation", MyTranslation3DObject);

This way we give names to Axis Rotation 3D and Translate Transform 3D objects and then in double animations refer them as Storyboard.SetTargetName(.., "AxisRotation") and Storyboard.SetTargetName(.., "TranslateTransformation") and access their direct properties such as Storyboard.SetTargetProperty(.., new PropertyPath("Angle")) and Storyboard.SetTargetProperty(.., new PropertyPath("OffsetX")) resp.