Slicer for Fusion 360 will do the exact chopping of cardboard you are asking for.
Zbrush still not cheap but if it’s just one sasquatch face you need to modify the 30 day free trial is plenty of time. Warning: it’s not like any other 3D program, totally different interface and tools. Do go through at least an intro tutorial or you’ll go mad!
True – designed by a sculptor for artists-- it is the closest thing I’ve used to actually sculpting in clay.
So, just an update, I have made a trade deal with a good Zbrush modeler. He’s working on a good sasquatch for me. Next I’ll have to try figuring out just how to do the slicing thing. Starting to save up a pile of useful cardboard at work. 
I’ve not tried it personally, but I’d think the open-source Slic3r utility should be worth checking out. It claims to ingest STL/OBJ meshes and output SVG files.
Unless you’ve already devised a method, some sort of layer registration may be needed before generating the SVG slices. This way, the Glowforged layers drop onto a peg and are aligned perfectly.
I may try using Meshmixer to subtract a hole or two from the model before going to Sliv3r to use for registration as the layers go on.
Slicr has several options to do exactly this, as well as label your layers, create assembly instructions and optimize/estimate part-layout-on-material :). There are even several cardboard types in the default material library. Not bad for free.
Wow, I need to get to learning slic3r. I’m waiting on the 3d model, but should have it any day now.