Nylon and polyester are woven into light fabric, often ripstop. Both soak up less water than cotton, but neither is waterproof on its own.

A thin layer of polyurethane is spread on one face, or liquid silicone is soaked into both faces to make silnylon. The coating, not the weave, keeps the rain out.

A technician measures a pitched frame and draws each wall at full size on paper. Marks on the paper show where zippers, hooks and guy points go. Cutters stack fabric in layers on tables often more than 10 meters long and trace every pattern.

Machinists start with ties, zipper ends and door panels, then work outward to larger pieces. The marks on each panel tell them where every fitting goes.

Walls are stitched to the door section and long pole sleeves go on. At this stage the shell is nearly complete, with only the floor missing.

Heat and pressure bond waterproof tape over the stitch lines on better tents, done before the floor goes in. Poorly applied tape bubbles and lifts.

The groundsheet is the last big piece stitched on. Family tents often use a polyethylene floor.

Cheaper frames use fiberglass tube less than 1 cm across, and stronger ones use aluminum alloy. Poles are checked for length, diameter and fit alongside sewing.

Some makers pitch every single unit, check it, then roll it up with its poles, pegs and guy lines in a carry sack.