>>1273919the plan is to melt in groves to make it fold up like the Thermarest Z-lite in a Zig-zag pattern. (it's the same material after all, just waffle-ironed into the egg carton shape)
For this you can use a hotblade or a soldering iron with a broad tip on a guide rail to maintain a uniform depth and stay strait.
i just have to decide on the form factor, if square like the z lite or flat like the german army pad. not sure yet if i want a flatter backpack wide thing with less folds or the more flexible square size.