Inserting a vector into a 3-d image and more

Hey everyone,

So the problem I'm working on is as follows:

I have point cloud format cells that when ran through the isosurface command look as such:

http://i.imgur.com/6lRkmwF.jpg

I also have the long axis eigenvector for these cells.

What I want to do is insert a vector with the properties of the long axis eigenvector into a surface plot of each cell and run along this vector calculating the surface area of the cell on either side of the point with a plane perpendicular to the vector as the dividing plane, and have this script return me the point at which this happens.

If anyone needs clarifying remarks about what's going on or what I want out of this don't hesitate to ask!

Thanks