No idea where to start

Hi guys, I use two cnc machines that I built for my business which is
cutting foam for signs or exterior window trim on houses and
commercial buildings.
Ive built a cnc machine to cut a certain product that I sell a lot
of. What im having problems with is developing a tool path that will
work.
I guess my other machines use the most basic of cnc, because I really
lack the knowledge to accomplish what I need. Its simple enough, but
out of my grasp, here is my prob. Imagine the machine as a 4 axis
mill. x y z being the standard use axis, and my A axis, instead of
rotating a workpiece, slowly rotates a cutting tool so that it
remains perpendicular to the direction of cutting. Sort of like a
vinyl lettering cutter where the knife is always turned into the
cutting direction. I have Bobcad and deskcnc. Between the two I
dont think I can accomplish it, desk cnc only uses dxf and stl files,
and my bobcad saves in many files formats, but nothing deskcnc will
use. Anyone have an idea for me, or perhaps a software suggestion?
Email me if you like at erase42@....
sorry if this is off topic for this forum, it seemed to cover just
about everything.

Ed Rees