Find Center of Mass of Mesh and set it for Rigidbody calculations

How do you find the center of mass of a mesh? I have a mesh model of a cat. The tail in the default pose is stretched out as long as the body of the cat so that the center of the bounding box of the mesh is not the actual center of mass. If the center of mass can be found how do you direct unity to do all rotations and rigidbody calculations from the new center?

You can do something like this:

by just eyeballing where you would like the pivot point to be.

Otherwise I imagine you would want to revisit the model in your modeling application. Blender is free if you don’t have one and change it’s origin that way. Then reimport in unity.