To me they look like the pants I'm currently making for Gaius
. I went by the pattern here
, changing the length and fabric choice to make more sense for what I need. Just make sure to measure/cut a little long so you get that full/drape/whatever effect around the boots.
What I would do to get the angular design on the pants would be to sew up the leg tubes first, pattern out (with some temporary marking-- Water soluble chalk, tailor's pencil, etc) where I'd want them to go, rip the seams, put on your design with the two pieces separate (either with fabric paint or applique
, then sew the pants together normally (center seam, inseam, out seam, waist, cuff).
While you're doing the tough bits, try to have the trophy screen up to have a 3D model to reference every step. It really helped me out with my Sheik cosplay, let me tell you.
EDIT: HAH, I thought you were looking for suggestions on how to make them. I'm so cool. Anyway, if you're planning to shop in person, check out the bottomweights/sportswear section of your fabric store, because his pants are a very specific color and it'd be a pain to look for a particular weave in a particular material in that color. Just avoid the corduroy section, that'd be a little odd.