Cutting lightweight fabric panels for specialized sleeping bags and quilts can be tricky.
Here is a panel of Primaloft One insulation that we quilt in-house with a custom made rig. We're sewing this panel into a Cathedral backpacking quilt. But cutting nylon with a knife or scissors leaves ends that can fray and weaken the stitching. Cutting with a hot knife not only seals the edges of the fabric, but also bonds multiple layers of material together, making our stitching more precise.
Some of the tools we employ to cut panels like this are:
Butane powered hot knife.
Magnets (also good for holding down curves).
Various pieces of metal from the backyard junk pile. I mean, "resource" pile.