Deforming an object based on collision.

I have a signpost object that I was wondering how I could get it to bend or knock down when hit by a rigidbody object? Any help would be appreciated

there are multiple ways 1 you can create it in multiple parts and connect them using joints and then break joints in result of a collision. 2 you can animate it's nocking and run the naimation after collision 3 if unity adds support for soft bodies in unity 3 or support fractures better you can implement this in a more natural way.