Hair
Turn curves into strands that swing, bend, and collide — keeping their length so they never stretch into spaghetti.
The Hair Sim node takes strands (curves or point chains) and brings them to life. Each strand keeps its length, resists bending, and bumps into the colliders and surfaces around it. Use it for hair, fur, grass, ropes, wires, or any long flexible thing.
Feeding it strands
Hair works on curves — long chains of points where each point follows the one before it. Lay out your strands first (scatter roots, draw guides, or grow curves), then wire them into simulation.hair. Drop the node into a feedback loop so the motion carries from frame to frame.
You don't need to convert anything by hand — strands feed straight in, and DNA handles the conversion automatically.
The first point of every strand is treated as the root and held in place. That's what pins your hair to a scalp or grass to the ground while the rest of the strand swings freely.
What the solver does
Three forces shape every strand, all resolved together each cook:
Length — segments stay the length they started at, so strands never stretch or collapse. This is the inextensibility that keeps hair looking like hair.
Bend — strands resist kinking and want to return toward their rest shape. More bend resistance gives you stiff bristles; less gives you soft, floppy locks.
Collisions — strands push out of colliders, surfaces, and (optionally) each other.
Everything runs on the GPU and updates live as you play, so you can dial bend and damping while watching the result move.
Parameters
| Parameter | Type | Default |
|---|---|---|
input | CollectionOf(Geometry) | — |
pin_group | String | "" |
iterations | Number | 10 |
stretch_compliance | Number | 0 |
bend_compliance | Number | 0.001 |
damping | Number | 0.010 |
stiffness_falloff | Number | 0 |
strength | Number | 1 |
Colliding with the world
Wire colliders and surfaces into your physics setup and hair will respect them — grass parting around a rolling ball, fur pressing against a body. You can also push strands around with a Force Field for wind, turbulence, or a gust on a beat.
Very dense, high-resolution strands (lots of segments) are the heaviest case for the solver. If motion looks unstable on extremely fine hair, reduce the segment count per strand or raise the solver's iterations. See Making it faster.
See also
Forces & collisions — colliders, ground, and contact
Cloth — the sibling solver for sheets and fabric
Curves (lines & paths) — how strands are stored
Loops & feedback — carrying motion across frames
simulation.force_field — wind and turbulence