public ShadowCastingMode shadowCastingMode { get; set; }

ShadowCastingMode enum defines how and if shadows are cast from this object. Typically shadows are either cast or not, but it's also possible to make shadows two-sided (useful for otherwise single-sided geometry) or make a shadows-only object (that is otherwise invisible in the Scene, but casts a shadow).

Additional Resources: ShadowCastingMode, Renderer.receiveShadows, Light.shadows.