“I want directional light to cast shadows for static meshes.So it has to be ON.”
I am not sure what you mean by this. All types of directional lights will cast shadows on your static meshes. For static, this will be in the form of a baked lightmap. For stationary, this will be in the form of a baked shadowmap (but the dynamic specular and n dot L part is still dynamic). For dynamic, the shadowing and light contribution are both dynamic.
It seems we are talking past eachother a bit so I am just trying to get on the same page. What has to be ‘ON’?
‘Light as if Static’ doesn’t depend on your lighting type, it is more about how the actors light. But a dynamic light will still dynamically light an object that is set to “light as if static”, it just means it will lightmap any available static lighting.