VecFlow0.1.0
FlowsOperators

Pin

Hold particles still, or move them with an object: hang cloth by its corners, tie a rope to something, carry kinematic rigid bodies.

VecFlow 0.1.0

Hold particles still, or move them with an object. Bound and bumping particles give way to them. Kinematic rigid bodies move and turn with the object.

Add it
EventAdd OperatorPhysicsPin
Sends on
Nothing: it has no wire.
Influence
No: a value can’t weigh it.

When to use it

  • Hanging cloth and ropes by some of their particles: the corners of a sheet, the top of a curtain, a rope's end.
  • Carrying things with an object: a flag on a moving pole, cloth on a character's shoulders.
  • Moving kinematic rigid bodies: a paddle or a wrecking ball, turning with its object.

Set it up

Pin acts on every particle in its event, so put the particles to hold in an event of their own. For cloth, a Group Test sends the vertices in a vertex group there:

A flow of 2 events. Sheet: Birth, Group Test, Gravity, Bind; Group Test: 'top' above 0.5 sends to Held. Held: Pin.SheetGroup Test: 'top' above 0.5Bind: mesh edgesBirth: on Sheet's vertices at frame 1. Make new particles: some every frame, all at once, one on each vertex of an object's mesh (for cloth and ropes: bind them with Bind, Mesh Edges), one on each piece of it (to smash: glue them with Bind, Pieces), or the event's Liquid filling itBirth: on Sheet's vertices at fr…Group Test: 'top' above 0.5. Particles born on an object's vertices go along the wire where the vertex weighs more than a value in a vertex group: say to an event with Pin, to hang cloth by its cornersGroup Test: 'top' above 0.5Gravity: 9.81 m/s². Pull particles down, or any way you point itGravity: 9.81 m/s²Bind: mesh edges. Hold particles together: soft bodies, ropes, cloth, sticky goo, things that tear. Binds hold wherever the particles go, until they break. Rigid bodies they hold turn on joints: chains, doors, ropes with crates. Particles losing a bind go along the wireBind: mesh edgesInHeldPin: in place. Hold particles still, or move them with an object. Bound and bumping particles give way to them. Kinematic rigid bodies move and turn with the objectPin: in placeIn
A curtain hanging from its top edge. Binds hold across events, so the held particles carry the rest.BirthForcesPhysicsLooksTests

Settings

As the flow editor’s sidebar shows them. Changing any of them marks the bake old; none of them can change through a bake.

Object
None

The object this operator works with.

With no Object, particles hold still where they are. With one, each goes where the object takes the spot it's on: moving, turning and scaling with it.

Pinned particles don't bounce off colliders. Bound and bumping particles give way to them.

A particle sent to Pin by a Group Test starts being held a step after it's born, so pinned corners first drop a few millimetres.

Works with

  • Bind: binds hold across events, so pinned particles hold up the cloth or rope they're part of.
  • Group Test to pick the particles to pin.
  • Rigid Body with Kinematic on, in the same event: the bodies move and turn with the object.
  • An event takes one Pin. It can't share an event with a Liquid, a Follow Curve or Goal, or a Rigid Body that isn't Kinematic.

Problems you may see

Error

event: operator: an event takes only one

Errors stop a bake; warnings don’t. Every message is on the Messages page.

Smoke Source

Particles give off smoke, heat and fuel into the flow's gas as they go: for plumes, trails, fire and explosions, saved as OpenVDB and shown as a volume.

Scale

Set the size of particles as they enter an event, with a random mix of sizes if you like.

On this page

When to use itSet it upSettingsWorks withProblems you may seeRelated