Gussets, Darts and Shape

everything sewn from cloth starts flat and ends up wrapped around something: a body, a cushion pad, a week's holiday packing. the whole craft of shaping comes down to three moves. take flat area away (darts), let corners open out (boxing), or add a wall of fabric between two panels (gussets). learn the three and every pattern you ever read afterwards is suddenly legible, because a pattern is just these moves written down.

the kit is small because shaping is technique, not tools. what it does demand is marking and pressing, done properly.

Darts: subtracting flatness

a dart is drawn as a long triangle: two legs meeting at a point. fold the fabric right sides together down the triangle's centre, match the legs, and sew from the wide end towards the point. the discipline is all at the tip: the last three or four stitches run nearly parallel to the fold, sewing off the edge to nothing, and the thread tails are tied rather than backstitched. press the dart to one side over a curved surface (a rolled towel works) and the fabric now cups. that cup is the entire secret of clothes that fit.

Boxed corners: width from nowhere

sew a simple bag: two rectangles joined at sides and base. it is flat as an envelope. now reach into a corner, flatten it so the side seam lies directly on the base seam, and a neat triangle forms. sew across that triangle at right angles to the seams, a measured distance from the point, and the envelope grows a rectangular base. the stitched line's length becomes the bag's depth. sew across at 8cm and the base is 8cm deep. every tote, wash bag and weekend bag base is this one move.

Gussets: adding a wall

a gusset adds fabric where boxing cannot. a strip gusset is a long band sewn between a bag's front and back panels, forming its sides and base in one piece: more sewing than boxing, but the shape is exact and the corners can be curved. the diamond gusset is the garment version, set into an underarm or the crotch of work trousers, adding movement precisely where seams otherwise tear. the pyjama course ahead uses this thinking; the weekend bag at the end of this path uses the strip.

Curves that lie flat

any curved seam fights you when turned. concave curves get clipped (straight snips into the allowance), convex curves get notched (small wedges cut out), both to within a couple of millimetres of the stitching. skip it and the seam bunches or strains; do it and the curve turns like it grew that way.