Not buildable in Clothix. Wovens are a later phase — the roadmap says when. This is the construction knowledge.
Rise
How to make pants, reduced to its first decision: get this number right and the rest follows.
Front rise is measured from the crotch seam up to the top of the waistband at centre front; back rise the same at centre back. They're different numbers, always, because a body is not symmetrical front to back — and the difference between them is what makes the waistband sit level.
Low, mid and high rise are marketing words for a spread of maybe 8 cm on the front rise. What changes with it isn't only where the waistband sits: the crotch depth changes, so the leg hangs from a different point and the whole silhouette moves. This is why you can't lower a rise by shortening the waistband.
Taper
Three measurements down the leg: thigh, knee, leg opening. Together they are the taper, and stating only the leg opening is the common gap — two trousers with the same 18 cm opening and a 6 cm difference at the knee are different garments.
Thigh is measured a stated distance below the crotch, and the distance has to be in the spec or the measurement isn't repeatable.
Waistband
Straight or curved, and it matters more than it sounds. A straight band is simpler and cheaper and gapes at the back on most bodies, because a waist slopes. A curved band follows that slope and sits.
Then the closure — a fly with a zip, a button fly, or an elasticated or drawcord waist, which is a different garment and a much cheaper one. And the interlining, which is what stops the band folding over in wear; a band with no interlining collapses whatever else you do.
Fly
Five pieces and a bar tack, described on the jeans page because it's identical. The one difference on a tailored trouser is that the fly is usually cleaner-finished inside, with a lined shield, which is more work and invisible.
The fabric decision
Almost always a twill, and the reason is mechanical: a twill drapes better and resists abrasion better than a plain weave at the same weight, and trousers get abraded constantly. Chino cloth for something smooth, drill for workwear, gabardine for something that holds a crease.
Weight range is roughly 240 to 340 g/m² for most trousers. Below 240 the fabric drapes without structure and the crease won't hold; above 340 the seams get bulky at the crotch point, which is already four or six plies.
Points of measure
Twelve to fifteen: waist relaxed, waist stretched if there's elastic, hip, front rise, back rise, thigh, knee, leg opening, inseam, outseam, waistband height, fly length, and the crotch seam length. Plus pocket dimensions and positions.
The consistency check that catches most errors: inseam plus front rise should agree with the outseam minus the waistband height, within a centimetre. If it doesn't, one of the four is wrong and the pattern will tell you which. How to take each one.
Twill weaves · jeans construction · measuring a finished garment · all categories · when wovens arrive