Cross Section Plane

Hi all,

Wondering if anyone can help, I have a laser scan of a 3D object and the scan came out pretty poorly and so I need to rebuild it a bit. The issue is that its not in line with any of the planes and has no flat surfaces to sketch on. I just need to put a plane through it so I can draw the cross section and rebuild it by lofting it from some key cross sections along the length of the part.

Combining the fact that it is not in line with any of the default planes and that it has no flat surfaces I'm really struggling to get a plane through it as a cross section, i know its possible cause the person who scanned it for me showed me, but i have since clearly forgotten how he did it and now cant do it.

I have attatched the file so that its easier to see what I am trying to explain.

Any help would be appreciated greatly

SolidworksParts And Features