We were recently presented with some very pretty round covers with a knife edge (knife edge is two pieces of fabric sewn together, like a bed pillow) and asked to make very firm inserts so that the client could use them as floor cushions. Unlike a sofa cushion which has a boxing panel sewn in which allows for the blockiness of a foam core, a knife edge seam doesn't fit a foam insert. Our solution was to shave down the edge of the foam to make it sharp which will neatly fit with the cover's seam. We then wrapped the foam with polyester which softens further the shape of the foam and takes the slack out of the fabric, tightening it and removing wrinkles. Once the inserts are installed in the covers, a full, firm insert is ready for the home.