Chapter 1: Weaves & Knits — Stretch and Hang

Created by Sarah Choi (prompt writer using ChatGPT)

Weaves & Knits — Stretch and Hang

Textiles are engineered behaviors. The way a cloth stretches, recovers, and hangs is set first by its structure—woven, knitted, felted, laminated—long before fiber chemistry or surface finish. For character concept artists, understanding structure offers reliable predictions for silhouette, fold families, seam logic, and wear. For production, it clarifies how to skin rigs, constrain cloth‑sim, and paint believable material response across LODs. This article maps the practical physics of weaves and knits, extends into leather and synthetics, and ties everything back to pattern and construction so your designs read credibly from block‑in to final package.

Grain, Bias, and Anisotropy: The Root of “Hang”

Woven cloth is anisotropic: it behaves differently along warp (lengthwise), weft (crosswise), and bias (45°). Warp is usually stronger and less stretchy; weft can offer marginal give; bias drapes and spirals. Designers exploit this by rotating pattern pieces to tune hang—skirts cut on the bias for swirl, bodices on straight grain for stability, capes on cross grain to encourage lateral fold ladders. Knits are more isotropic, with loop structures giving multi‑directional stretch and recovery, but even knits have course‑wale asymmetries (horizontal vs vertical). Your silhouette choices should echo these truths: flat, planar hangs for straight‑grain woven capes; liquid, spiral movement for bias cuts; elastic contouring for rib knits.

Weaves: Plain, Twill, Satin, and Friends

Plain weaves interlace over‑under uniformly, producing crisp, stable drape and quicker “break” in folds. Twills step the interlace to create diagonal ribs that resist wrinkles and bend cleanly along their rib direction—ideal for pants, coats, and military garments where abrasion resistance and clear fold creases matter. Satin/sateen floats increase sheen and fluidity but snag more easily; they read luxurious, with broad, soft highlight bands. Basket, herringbone, and jacquard variants alter weight and surface pattern while largely preserving the parent family’s mechanics. In concept art, render plain weaves with tight, narrow specular and sharp fold edges; twills with faint diagonal texture and decisive creases; satins with larger, softer highlight blooms and deeper shadow cores.

Knits: Jersey, Rib, Interlock, and Spacer

Knits form loops rather than interlacing yarns, storing elastic potential energy in those loops. Jersey (single knit) curls at edges and stretches more horizontally, reading casual and clingy; interlock (double knit) is thicker, more stable, and hangs cleaner; rib knits oscillate columns of knit and purl for high stretch, making cuffs and base layers that grip but don’t cut circulation. Spacer knits sandwich a monofilament mesh between faces to create breathable, springy panels used in performance wear and padded under‑armor zones. When drawing, suggest knits with rounded fold tops, softer shadow turns, and minimal crisp creasing unless heavily tensioned; edge curl is a tell for jersey, while rib knits exhibit periodic micro‑striping and controlled recoil at hems and cuffs.

Nonwovens, Felts, and Laminates

Nonwovens bond fibers by heat, solvent, or needle‑punch; they behave like paper—stable until creased, then memory‑holding. Felts mat fibers into dense, nearly isotropic sheets with slow, sculptural folds and excellent wind resistance. Laminates marry a face textile to a membrane (waterproof‑breathable films) and/or backer; they bend in broad arcs and resist tiny wrinkles, reading as “shell” rather than “cloth.” Use these for outerwear and armor‑adjacent pieces: folds become larger‑radius with persistent kinks where compressed, and seam taping and panel edges read as engineering over ornament.

Leather: Skin as Sheet Material

Leather is collagen architecture: grain side dense and smooth, flesh side open. It stretches more along the belly direction and less along backbone; pattern makers place high‑stress pieces along tighter areas to control growth. Vegetable‑tanned leathers are stiff initially and mold with heat and moisture, taking crisp creases that polish at edges; chrome‑tanned leathers are softer with pliant drape and less edge burnish. Suede splits display nap that darkens when brushed; nubuck is sanded grain with fine, velvety bloom. In painting, drive the story with compress‑shine on elbows and knees, a halo of burnish along straps and hems, and subtle waviness where leather has stretched under load. Stitching bites create raised channels (seam swell) and reinforce the illusion of thickness; hardware radiates wear halos where metal abrades finish.

Synthetics and Performance Fabrics

Polyamide/nylon and polyester blends dominate technical wear. High‑tenacity weaves (Cordura‑like) resist abrasion and keep sharp fold edges; microfibers produce peach‑skin hand that kills specular for stealth; stretch fibers (spandex/elastane) add recovery that smooths wrinkles and reduces fold count. Membrane shells (PU, PTFE) shift from cloth to quasi‑shell behavior in wind and rain; water beads alter highlight breakup. Spacer meshes and open weaves ventilate—read them with subsurface shadow and parallax between layers. For sci‑fi, you can justify exotic laminates and conductive weaves; still ground them by showing predictable seam reinforcement, vent placement, and grain‑respecting panel shapes.

Hard Surfaces Adjacent to Cloth

Many character kits blend textiles with rigid elements—armor plates, composites, plastics. The junction language matters. Soft goods should pouch and blister slightly around rivets and plate edges; plates should float on webbing or elastics to preserve motion read. Depict stitch lines, bar tacks, and binding tapes where textiles meet hard surfaces. In rig/sim, convert these junctions into constraints: pin groups for stitch locations, sliding constraints under webbing, and collision proxies for plates so cloth doesn’t interpenetrate during crouch and sprint.

Fit, Pattern, and Seam Logic by Structure

Wovens prefer darts, princess seams, and gussets to shape around convex forms; they resist tight curvature without those aids. Knits can map closer to body with fewer seams but need recovery zones (ribs, elastic) to prevent growth. Felts and laminates shape via darts, steam, and paneling with larger radii. Leather wants strategic seams that avoid high‑stretch directions, with topstitching that compounds strength. Translate these truths to pattern maps: rotate elbow seams off pressure lines, add diamond gussets at crotch for woven pants, bias‑cut gores for skirts, knit collars with self‑finish rather than bound edges, and leather panels that break near natural hide boundaries. Closure scale follows structure: knits favor coil zips and covered plackets that won’t snag loops; wovens tolerate button stacks and lacing; laminates and leather like chunky zips and toggles that index by feel.

Fold Families by Structure

Plain‑weave cloaks form knife folds and accordion stacks that reset quickly when shaken. Twill trousers exhibit decisive creases that persist at knees and hips. Satins flow into s‑curves with broad specular “rivers.” Jerseys pool with rounded humps and shoulder draglines; ribs retract and reduce fold count after motion. Felts bend into slow arcs with minimal micro‑wrinkle. Laminates kink at hinge lines near seam allowances and stay flat elsewhere. Leather shows radius‑limited bends with polish at convexes and “elephanting” (fine grain cracking) on over‑stressed zones. Use these families to pick believable drapery in thumbnails before you commit to material paint.

Painting and Shader Notes

At mid‑distance, communicate structure with edge behavior and highlight size more than weave texture. Reserve visible weave grids for extreme close‑ups or macro props. For wovens, sharpen fold crests and add short, broken micro‑wrinkles at stress lines; for knits, soften crests and introduce subtle directional ribbing where light rakes; for satins, widen highlights and deepen core shadows; for laminates, keep specular tight and coherent across large panels; for leather, layer a base sheen with wear‑map masks for burnish, dryness, and oiling. Add anisotropic roughness for twills and moiré‑like breakup for jacquards only when camera warrants. In-engine, tie normal detail to camera distance and motion so folds don’t shimmer.

Wear, Aging, and Repair by Material

Wovens fray at cut edges and abrade at protrusions; patches and darns add orthogonal thread logic to surfaces. Knits ladder when cut and pill under friction; repairs read as whipstitch or applied patches that stop run spread. Leather dries and craze‑cracks, especially at bend radii; conditioning darkens and unifies sheen. Laminates delaminate at edges and blister with heat damage; seam tape peels before face fabric fails. Use repair language appropriate to structure: sashiko‑like reinforcement for woven knees, fusible patches for shells, bar‑tacked webbing for harness wear, and stitched or riveted scabs for leather.

Rigging and Cloth‑Sim Guidance

Declare structure in your callouts so tech teams can choose constraints wisely. Wovens: higher bend resistance on straight grain, lower on bias; allow shear within small ranges; enable crumple only where ease exists. Knits: higher stretch limits and faster recovery with damping to prevent oscillation; simulate rib cuffs as elastic constraints rather than geometry. Laminates: low stretch, higher bend stiffness, minimal crumple; add wind interaction for readable shell flutter. Leather: moderate stretch with plastic deformation over time; bias stretch negligible; collision thickness higher to prevent clipping through plates. Mark anchor points, gussets, and slits that should behave differently than the surrounding field.

Production Packaging: What to Label

For every major garment, include a structure tag (woven/knit/felt/laminate/leather), expected grain direction per panel, ease amounts at key joints, and intended fold family reference. Note seam types (plain, flat‑felled, bound), stitch density, and tape widths where applicable. Provide wet/dust/frost variants only after structure is locked; environmental passes amplify behavior but cannot fix implausible hang. Add a wear map that explains not just “where” but “why” the material aged.

Closing Thought

When you can predict how a fabric will bend, stretch, and recover, you stop decorating and start engineering silhouettes that move with the character and the story. Let structure lead, let pattern respect structure, and let surface finish be the last, delightful 10%. Your designs will read truer at every camera distance and your production partners will thank you for garments that simulate and render like the materials they pretend to be.