Capaciflector problem

I am trying to do a project using a capaciflector to measure the distance of the object. Its been awhile since I fooled with electromagnetics so I read up on capaciflectors. My question though is looking through my electro book and articles, what equations would I use to solve for capacitance, and find the direction of field? or am I still off in left field and need to do more reading? Either way, what is a good source for me to look at that will help me out.

Thanks,
Bob