もう少し簡単に書けるといいんだけど・・・
Transform3DGroup tg = new Transform3DGroup();
tg.Children.Add(new TranslateTransform3D());
tg.Children.Add(new RotateTransform3D(new AxisAngleRotation3D(new Vector3D(1, 0, 0), this.Slider.Value *30)));
tg.Children.Add(new ScaleTransform3D());
tg.Children.Add(new TranslateTransform3D());
tg.Children.Add(new RotateTransform3D(new AxisAngleRotation3D(new Vector3D(1, 0, 0), this.Slider.Value *30)));
tg.Children.Add(new ScaleTransform3D());
this.BoxOR9GR10.Transform = tg;