How to make mesh particles lay flat on ground

Any ideas how I can make my mesh particles (shards of glass) spin in the air on emission but then land flat on the ground.

Personally I would animate them inside the shader/vertex animation/skeletal mesh, that way you have control over when they need to fall flat. I dont think there is a proper way of doing it otherwise.

So my suggestions would be to look up on how to bake vertex animations or set it up as a skeletal mesh.

Not to mention that each emitted mesh is a drawcall, a shattered glass effect could turn out a massive fps/drawcall killer.