SC Shadow is a powerful shadow customizer. Works with any alpha channel whether applied by Effects Masks or Draw Mask and Shape Mask.
Independent positioning of source and shadows can be accomplished. Shadow distortions like scale, rotation, shear, etc. are available.
Shadows may be solid or gradients (think gradient opacity so they can be faded over distance!)
Requires FCPX 10.4.10 or higher. May be backdated to 10.4. To be installed as an Effect.