Hair¶
The hair solver is a Verlet rope: a chain of N point masses connected by stiff distance constraints. Use it for hair, ropes, tails, antennae, and any "string" that should swing and respond to motion.
Create¶
| Menu | What you get |
|---|---|
Simulation > Create Hair Strand |
8-segment short strand |
Simulation > Create Long Hair Strand |
24-segment long strand |
A vertical chain appears at the cursor. The first (topmost) vertex is pinned by default; the rest hang.
Anchor to a placement¶
Most hair strands should follow some other placement (a head, a sword pommel, a wing). Set the anchor:
- Select the hair.
- Properties pane > Simulation > Anchor > pick a target placement from the scene.
- The hair's first vertex follows the anchor's transform.
Move the anchor, the hair sways. Animate the anchor, the hair inherits the motion plus its own physical lag.
Parameters¶
| Parameter | Default | Effect |
|---|---|---|
| segments | 8 / 24 | Chain segment count |
| segment_length | auto | Distance between vertices |
| stiffness | 0.7 | Constraint solver stiffness |
| damping | 0.1 | Velocity damping |
| gravity_scale | 1.0 | Multiplier on global gravity |
| affected_by_wind | true | Whether forces apply |
| collide | false | Whether to collide with collider placements |
Wind sensitivity¶
Hair reacts strongly to wind: even a gentle wind produces visible
sway. Tune by scaling wind strength globally and / or per-strand
via gravity_scale (which also scales wind in this solver).
For multiple hairs that should sway differently (long vs short), use the same wind but different segment counts and stiffness; the differences in resonance create natural variation.
Multi-strand setup¶
For hair groups, drop multiple Create Hair Strand placements
side by side and parent them to a common head. The wind affects
each independently; their slight phase offsets read as a hair
clump.
For thousands of strands, this approach does not scale. Roadmap: a Hair System solver that simulates a base set and instances the rest.
Rendering¶
A hair strand renders as a stroked Bezier curve following its
vertex positions, with the placement's stroke + stroke_width
applied. For a tapered look (thick at root, thin at tip), set
width_modulation: distance_from_root in the Properties pane.
Use as rope¶
Rope is the same solver with stiffness raised to 0.95 and
segments increased. For a cable or chain, also set damping to
0.3 (rope swings less).
Bake¶
Like cloth, hair sim auto-caches per frame. Simulation > Bake to
Keys collapses to per-frame keys for export.