Skin families

Generate many related skins (teams, factions, rarity tiers, colorways) from one base spec and a few variants. One file, dozens of consistent skins.

A family is a document with "kind": "family", a base skin spec, and members defined by variants (explicit list), a matrix (cartesian product of axes), or both.

{
  "version": 1,
  "kind": "family",
  "name": "Guild uniforms",
  "base": { "version": 1, "palette": { "primary": "#9b2f2f", "trim": "#e0a940" }, "layers": [ ... ] },
  "matrix": {
    "guild": {
      "ember": { "palette": { "primary": "#9b2f2f" } },
      "tide":  { "palette": { "primary": "#2c5d9b" } }
    },
    "rank": {
      "recruit": { "disable": ["trim"] },
      "captain": { "enable": ["cape", "insignia"] }
    }
  }
}

This expands to four members: ember-recruit, ember-captain, tide-recruit, tide-captain. See the complete guild example.

#Variant patches

Every variant (and every matrix axis value) is a patch applied to a copy of the base: it recolors, toggles layers by id, changes base layers by id with the same entries as a spec patch, and appends layers. Recolors make a set of colorways; patch makes a cast: one face angry and another smiling, a beard here, a hood there, all on one shared base.

Matrix patches are applied in axis order, so later axes win on conflicts.

"variants": {
  "captain": { "patch": [{ "do": "update", "id": "face", "set": { "eyeStyle": "angry", "beard": "full" } }] },
  "medic":   { "palette": { "primary": "#e8e8e8" }, "patch": [{ "do": "replace", "id": "emblem", "layer": { "op": "pixels", "target": "body.front", "x": 3, "y": 3, "rows": ["R.", "RR"], "legend": { "R": "#c02020" } } }] }
}

#Designing a good family

1. Perfect the base first. Render it alone until it passes the rubric; every flaw is multiplied by the member count.
2. Name colors by role, not hue. primary, secondary, trim, accent, so variants only swap values. Derive shades from them ("primaryDark": "primary:-12") and the whole ramp follows.
3. Optional details get ids. Capes, badges, helmets, rank stripes: add them to the base with "enabled": false and an id, then enable them per variant. Several layers can share one id and toggle together. Give the face, the hair and the main garment ids too, so a variant can patch them into another character.
4. Distinguishable at a glance. Check the lineup: members should differ in value or silhouette, not just hue.
5. Member ids are lowercase letters, digits and -. Matrix ids join axis values with -. The limit is 256 members.

#Rendering families

The lineup shows each member's front and back, in expansion order (variants first, then matrix combinations).