ModelVisual3D.Content Property

<DockPanel>
  <Viewport3D Name="myViewport">

    <Viewport3D.Camera>
      <PerspectiveCamera FarPlaneDistance="20" LookDirection="5,-2,-3" UpDirection="0,1,0" NearPlaneDistance="0" Position="-5,2,3" FieldOfView="45" />
    </Viewport3D.Camera>

    <ModelVisual3D x:Name="topModelVisual3D">
      <ModelVisual3D.Children>
        <ModelVisual3D>
          <ModelVisual3D.Content>
            <DirectionalLight Color="#FFFFFFFF" Direction="-3,-4,-5" />
          </ModelVisual3D.Content>
        </ModelVisual3D>

        <ModelVisual3D>
          <ModelVisual3D.Content>
            <GeometryModel3D Geometry="{StaticResource myTeapot}">
              <GeometryModel3D.Material>
                <DiffuseMaterial>
                  <DiffuseMaterial.Brush>
                    <SolidColorBrush Color="Blue" Opacity="1.0" />
                  </DiffuseMaterial.Brush>
                </DiffuseMaterial>
              </GeometryModel3D.Material>
              <GeometryModel3D.Transform>
                <RotateTransform3D>
                  <RotateTransform3D.Rotation>
                    <AxisAngleRotation3D x:Name="myAngleRotation" Axis="0,3,0" Angle="1" />
                  </RotateTransform3D.Rotation>
                </RotateTransform3D>
              </GeometryModel3D.Transform>
            </GeometryModel3D>
          </ModelVisual3D.Content>
        </ModelVisual3D>


      </ModelVisual3D.Children>
    </ModelVisual3D>


    <Viewport3D.Triggers>

      <EventTrigger RoutedEvent="Viewport3D.Loaded">
        <BeginStoryboard>
          <Storyboard>
            <DoubleAnimation 
              Storyboard.TargetName="myAngleRotation"
              Storyboard.TargetProperty="Angle"
              From="0" To="360" Duration="0:0:10"
              RepeatBehavior="Forever" />
          </Storyboard>
        </BeginStoryboard>
      </EventTrigger>
    </Viewport3D.Triggers>


  </Viewport3D>
</DockPanel>