Getting Mass on a specific point?

Hello I want to get the Mass (weight) on a specific point of a gameobject.

I want to make a Bridge Builder Clone (You know this little old game?) http://personal.brandongreenlee.com/wp-content/uploads/2008/05/bridge_builder.jpg

So I need to get the weight (Maybe Mass from Rigidbody?) on a specific point of a gameobject.

Is it also possible to make a triangle to get more stability? Because the carriers on the picture would increase the weight (Instead of release the other objects).

Thank you very much.

it's not possible to get the mass in a specific point on a object but if you want to make objects in a way to work correctly. you can change their center of mass in a script. you can calculate based on center of mass but you can not change the distribution of mass in different parts of the object. you can create compound objects for that.