use the camera clipping plane in ortho, but if you want to export a drawing...thats something else entirely

best is to take to rhino cut there

export your model as *.iges or *.igs file and then open it with rhino..there is a split command which is perfect for cutting sections.

wow, de ja vu. wasn't there an identical post to this not too long ago?

junkieonur has it right. do what he says.