/cloth-sim

name: cloth-sim
description: Garment blockout, cloth simulation, pin groups, and bake to shape keys or caches for characters and props in Blender via MCP.
license: MIT
metadata:
  author: https://github.com/arjun988
  version: "1.0.0"
  domain: blender
  role: specialist
  triggers: cloth, garment, clothing sim, fabric sim, pin group, shape key bake, cloth bake, dress, cape, soft clothing
  related-skills: character-artist, physics-sim, materials, animation, export-pipeline

Cloth Sim

Garment blockout → sim → art-direct → bake. Stable pins. Engine-friendly caches/shape keys.

When to Use

• Dresses, capes, coats, flags, banners
• Character clothing that needs drape
• Baking sim to shape keys or Alembic/USD caches
• Pre-roll settling before animation export

Workflow

Garment mesh (quad-friendly) → Vertex groups (pin/collide)
  → Cloth modifier settings → Collision objects
  → Pre-roll settle → Sim pass → Art-direct fixes
  → Bake shape keys / cache → Cleanup → Export

Mesh Prep

• Quads preferred; even density on deforming areas
• Avoid long skinny triangles on folds
• Apply scale before sim
• Separate garment from body collider

Vertex Groups

| Group | Purpose | |-------|---------| | `PIN_Cloth` | Anchors (waist, shoulders, collar) | | `COL_Ignore` | Optional non-colliding regions | | `STIFF_High` | Belts, seams that should resist stretch |

Settings Starters

| Look | Quality | Speed | Bending | |------|---------|-------|---------| | Soft dress | 8–12 | 1.0 | Low | | Stiff coat | 5–8 | 1.0 | Higher | | Flag/cape | 8–10 | 1.0–1.5 | Low–mid |

Tune mass and air viscosity for scale. Always run a settle pre-roll.

Bake Targets

| Target | Use | |--------|-----| | Shape keys | Game poses / few frames | | Alembic/USD | Cinematic caches | | Armature weights | If converting to deform-only |

Constraints

MUST DO

• Apply scale; define pin groups before long sims
• Collide against simplified body capsule/mesh
• Art-direct after sim (sculpt/corrective keys)

MUST NOT DO

• Sim hero cloth on ultra-dense sculpt meshes
• Skip pre-roll (starts mid-air / exploding)
• Export raw unstable caches

Reference Guide

| Topic | Reference | Load When | |-------|-----------|----------| | Cloth Settings Presets | `references/cloth-settings-presets.md` | When needed | | Pin And Collide | `references/pin-and-collide.md` | When needed | | Bake Targets | `references/bake-targets.md` | When needed |