 <p>If you need TransformGroup in your RenderTransorm, then StoryboardTargetProperty will be look like </p> <pre><code>RenderTransform.Children[0].Angle </code></pre> <p>If you leave only RotateTransform there, then it will be</p> <pre><code>RenderTransform.Angle </code></pre> <p>In both cases, as you see, we start searching property from <strong>RenderTransform</strong>. </p>