Inkscape / F-Engrave Question

I am relatively new to CAD/CAM and CNC and am trying to come up with a simple procedure for cutting a rectangular recess using Inkscape -> F-engrave -> LinuxCNC.

I have a rectangle drawn in Inkscape and fill it using the fill tool and then export it as DXF, but when opened with F-engrave, F-engrave sees only a rectanglular border not a filled rectangle. Same thing with DXF2GCODE. It only seems to be seeing the shape as a basic rectangle not a filled rectangle.

I assume that I am either not filling the rectangle properly in Inkscape or the "fill" information isn't making it into the DXF.

Everything else in the pipeline seems to be working well.

Any helpful suggestions would be greatly appreciated.

Thank you for your reply. As I mentioned I'm new to this. I am a long time C/C++ programmer, but haven't gotten around to learning to write G code by hand yet.

I believe pocket milling is what I am currently trying to do. I want to remove a precise rectangular solid from an arbitrary sized piece of MDF. From your link I see that pycam is listed. I have that as well and have been trying to get it to generate G code for a pocket cut using one of its included samples, Box0.stl. So far it looks like it wants to do the inverse of what I need, that is, cut everywhere around the rectangular solid.

Of course it helps if I read the manual more closely. Pocketing does seem to be supported. I had to select the engraving toolpath.
Time to experiment.