VecFlow0.1.0
FlowsOperators

Rotation

Turn particles as they enter an event: at random, pointing the way they move, or to set angles; and keep them turned every step if you like.

VecFlow 0.1.0

Turn particles entering the event: at random, along their motion, or to set angles.

Add it
EventAdd OperatorLooksRotation
Sends on
Nothing: it has no wire.
Influence
Yes: it does as much as a value says, particle by particle (0 none, 1 all of it).

When to use it

Rotation matters for particles shown as shapes, and for rigid bodies: a sphere looks the same any way round.

  • Random: debris, rocks, confetti and leaves, so no two land alike.
  • Along Motion: arrows, birds, fish, planes, sparks drawn as streaks: anything that points the way it goes.
  • Set Angles: all turned the same way, such as coins standing on edge.

Particles no Rotation has turned stay as their shape was modelled.

Set it up

A flow of one event. Birds: Birth, Position, Speed, Flock, Rotation.BirdsBirth: 60 all at once. 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: 60 all at oncePosition: Sky, volume. Place new particles in an object's box, on its surface or inside it, or along a curve (a tube round it)Position: Sky, volumeSpeed: 3 m/s. Set the speed of particles entering the event, along a direction (an object's own axes when given), or add it to how they comeSpeed: 3 m/sFlock: flock. Particles move together as a flock or a school: each keeps apart from the nearest few it sees, heads their way and keeps among them, cruising at its speed (with those of other events with this operator too). They turn aside from this event's Collide objects and ground before reaching themFlock: flockRotation: along motion, keep doing it, bank 1. Turn particles entering the event: at random, along their motion, or to set anglesRotation: along motion, keep doi…In
A flock of birds: Rotation keeps each pointing the way it flies, and leaning into its turns.BirthForcesPhysicsLooksTests

Settings

As the flow editor’s sidebar shows them. Changing any of them marks the bake old; those marked Keyframable can also change through a bake.

Turn
Random

Which way particles are turned.

  • Random: Each one turned at random.
  • Along Motion: Each one pointing the way it moves.
  • Set Angles: All turned the same way.
Axis
Z

The shape's own axis that points the way it moves. Its own Z keeps up (its Y, pointing along Z)

  • X
  • Y
  • Z
  • -X
  • -Y
  • -Z

Shown when Turn is Along Motion.

Angles
Keyframable
0, 0, 0

The angles every particle is turned to.

Shown when Turn is Set Angles.

Keep Doing It
Off

Every step, for every particle, not only when it arrives.

Shown when Turn is Along Motion or Set Angles.

Bank
Keyframable
00 to 2

How much they lean into turns: 1 as birds and planes do.

Shown when Turn is Along Motion, and Keep Doing It is on.

InfluenceEmpty

One of the flow’s number values, to weigh it by, particle by particle. Empty for all of it, on all of them. See Influence.

Along Motion

The shape's own Axis points the way the particle moves, and its own up (Z, or Y when Axis is Z or -Z) stays as near the world's up as it can. Model the shape pointing along that axis. A particle standing still keeps the way it faced.

Without Keep Doing It, a particle is turned once, as it enters. With it, it's turned every step, so it follows its path as it curves.

Bank

With Along Motion and Keep Doing It, Bank leans particles into their turns, as birds and planes do: 1 leans them as a real flyer would, more leans them further. It eases in, so they don't snap from side to side. Without Keep Doing It, Bank does nothing, and the editor warns.

Keep Doing It with Set Angles

Holds every particle at the Angles, every step. Keyframe Angles to turn them all together.

Works with

  • Spin turns them on from where Rotation left them. A Rotation with Keep Doing It sets their turn every step, so a Spin in the same event doesn't add up: use one or the other.
  • Rigid Body: a Rotation above it sets how bodies start, turned.
  • Goal has its own Face Targets, to turn particles as their targets are turned.
  • Influence: weighed by a value, a particle turns that share of the way. At 0.5, halfway.

Problems you may see

Warning

event: operator: Bank leans them into turns only with Keep Doing It on

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

Scale

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

Spin

Set particles tumbling as they enter an event, each about its own random axis, as fast as you like.

On this page

When to use itSet it upSettingsAlong MotionBankKeep Doing It with Set AnglesWorks withProblems you may seeRelated