Cloth¶
The cloth solver is a position-based-dynamics (PBD) mesh simulator suitable for flags, capes, banners, and any draping fabric.
Create¶
| Menu | What you get |
|---|---|
Simulation > Create nCloth Patch (8×10) |
80-vertex patch, fast iteration |
Simulation > Create nCloth Patch (12×14) |
168-vertex patch, more detail |
A flat rectangular sheet appears at the cursor. Use the Move tool to position it and the Rotate tool to orient.
Pin vertices¶
A cloth patch with no pinned vertices falls to the ground (or floats in zero gravity). Pin the corners or edge to attach it.
- With the cloth selected, switch to vertex mode (
V). - Lasso the vertices you want pinned.
Simulation > Cloth > Pin Selected Vertices.
Pinned vertices are locked to their initial positions (or, with Pin to Placement, glued to another placement's transform). A flag-pole + flag is pin-the-leftmost-vertices to the pole.
Parameters¶
In the Properties pane:
| Parameter | Default | Effect |
|---|---|---|
| stretch_stiffness | 0.95 | How resistant to stretching (1.0 = inextensible) |
| bend_stiffness | 0.5 | How resistant to folding |
| damping | 0.1 | Velocity damping per step |
| friction | 0.4 | Self-collision friction |
| thickness | 1.5 px | Self-collision thickness |
| affected_by_wind | true | Whether forces in the scene apply |
| iterations | 8 | PBD constraint iterations per step (more = stiffer / more stable) |
For a flag, default values work. For a stiff cape, raise bend_stiffness to 0.8. For a sheer veil, lower stretch_stiffness to 0.5.
Wind¶
Simulation > Forces > Add Wind… adds a global wind to the
scene. The cloth's affected_by_wind: true opts it in.
Wind parameters: direction (vector), strength (px/s²), turbulence (0..1), noise scale (in pixels).
A flag-on-pole with a 200 px/s² wind at 0.3 turbulence reads convincingly. Animate the wind direction over a few seconds for gusts.
Self-collision¶
Off by default (cheap). Toggle self_collide on in the Properties pane for capes that fold over themselves; runtime cost roughly 2x's.
Collision with other objects¶
The cloth collides with placements tagged as collider. Mark a placement as collider in its Properties pane > Simulation > Acts as Collider. Useful for a cloth draping over a model.
Cache¶
Running a simulation through the timeline auto-caches the result.
The cache lives next to the project file at
<project>.esk/sim_cache/<placement_id>.bin. Re-scrub plays back
from the cache instantly.
To force a re-sim: Simulation > Recompute Cache or change any
simulation parameter (the cache invalidates automatically).
Bake¶
Simulation > Bake to Keys writes per-frame keys for every vertex
on the cloth's animation track. The cloth-sim solver is then
removed; the placement plays back as a hand-keyed mesh.
Bake before exporting if you want predictable runtime behavior that does not depend on the runtime re-simulating.