VecFlow0.1.0
Effects guides

Sparks, dust and magic

Small, bright particles in streams and bursts: grinder sparks, fireworks, dust in a sunbeam, a trail of magic.

VecFlow 0.1.0

Sparks, dust and magic are all many small particles, born fast, short-lived, and lit by their colour. The tools are the same each time: how many are born, how they're sent off, how long they last, and how they look.

Start from

The Particles starter makes a stream from a small emitter, set by the sidebar's panels: enough for sparks and dust. For anything in stages (sparks that split, fireworks that burst) start from the Fountain, a flow of three events, or press Convert to Flow on a Particles simulation.

Grinder sparks

Without a flow, from the Particles starter:

Turn the emitter so its Z axis points the way the sparks fly. Particles go out along it.

In Emission: Per Frame 2000, Speed 8 m/s, Spread 3 m/s; under Lifespan, Life 0.8 s, give or take 0.4.

In Forces, leave Gravity at 9.81 and set Drag to 0.3. In Collisions, the Ground's Bounce 0.4, so they skip along the floor.

In Size, Spin and Colour, set Colour to Fixed: a deep orange, with a little Variation. (By Speed, the default, runs from white when fast through orange to blue when slow: handy for reading a bake, less so for sparks.)

In Display, make them small: Sphere Radius 0.003 m. Turn on Trails with 2 or 3 frames for streaks, or render with motion blur.

Fireworks

A rocket rises, then bursts into stars: two stages, so a flow.

A flow of 3 events. Rockets: Birth, Position, Speed, Gravity, Age Test; Age Test: at 1.2 s, give or take 0.2 sends to Burst. Burst: Spawn, Delete; Spawn: 150 each, spread 7 m/s sends to Stars. Stars: Colour, Gravity, Drag, Delete.RocketsAge Test: at 1.2 s, give or take…Birth: 1 per frame from 1 to 40. 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: 1 per frame from 1 to 40Position: Launcher, box. Place new particles in an object's box, on its surface or inside it, or along a curve (a tube round it)Position: Launcher, boxSpeed: 18 m/s, spread 2. 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: 18 m/s, spread 2Gravity: 9.81 m/s². Pull particles down, or any way you point itGravity: 9.81 m/s²Age Test: at 1.2 s, give or take 0.2. Particles reaching an age go along the wireAge Test: at 1.2 s, give or take…InBurstSpawn: 150 each, spread 7 m/sSpawn: 150 each, spread 7 m/s. Make new particles from each one, sent along the wire. They start with its looksSpawn: 150 each, spread 7 m/sDelete: at once. Remove particles at an age (since birth, or since entering this event), or at onceDelete: at onceInStarsColour: gold, variation 0.4. Set the colour of particles entering the eventColour: gold, variation 0.4Gravity: 3 m/s². Pull particles down, or any way you point itGravity: 3 m/s²Drag: 1.5. Slow particles to the speed of the air, which moves with the windDrag: 1.5Delete: at 1.5 s, give or take 0.5. Remove particles at an age (since birth, or since entering this event), or at onceDelete: at 1.5 s, give or take 0…In
Fireworks: each rocket goes to Burst at about 1.2 s, makes 150 stars and is removed; the stars slow, sag and fade out.BirthForcesPhysicsLooksTests
  • Spawn's Count makes that many from each particle as it enters Burst, and Spread throws them every way. Inherit Motion at 1 carries the rocket's motion on, so the burst drifts up with it.
  • A Delete at Age 0 removes the rocket the step it arrives, after Spawn has used it.
  • Colour in Stars, with a big Variation, gives each burst a mix of colours. For one colour a burst, set it in Rockets instead: stars keep their parent's colour.

Dust in a sunbeam

Dust hangs and drifts: no gravity to speak of, gentle swirls, nothing removed.

A flow of one event. Dust: Birth, Position, Turbulence, Drag, Colour.DustBirth: 5,000 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: 5,000 at frame 1Position: Room Air, volume. Place new particles in an object's box, on its surface or inside it, or along a curve (a tube round it)Position: Room Air, volumeTurbulence: strength 0.2, swirl size 1, change 0.1. Push particles around in swirlsTurbulence: strength 0.2, swirl…Drag: 1. Slow particles to the speed of the air, which moves with the windDrag: 1Colour: pale warm grey. Set the colour of particles entering the eventColour: pale warm greyIn
Dust motes: born once, through the room's air, and stirred slowly by Turbulence.BirthForcesPhysicsLooksTests

Keep the motes tiny (Sphere Radius 0.0015 m) and let the light do the work: a strong beam through them, the rest of the room dark. Render Multiply fills the air with many more than you bake.

A trail of magic

Particles shed by a moving wand, that rise and sparkle as they fade.

A flow of 2 events. Dust: Birth, Position, Speed, Gravity, Turbulence, Drag, Chance Test, Delete; Chance Test: 2 per second sends to Sparkle. Sparkle: Colour, Scale, Delete.DustChance Test: 2 per secondBirth: 800 per frame from 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: 800 per frame from 1Position: Wand Tip, volume, inherit 0.2. Place new particles in an object's box, on its surface or inside it, or along a curve (a tube round it)Position: Wand Tip, volume, inhe…Speed: 0 m/s, spread 0.3. 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: 0 m/s, spread 0.3Gravity: -0.3 m/s². Pull particles down, or any way you point itGravity: -0.3 m/s²Turbulence: strength 1. Push particles around in swirlsTurbulence: strength 1Drag: 3. Slow particles to the speed of the air, which moves with the windDrag: 3Chance Test: 2 per second. Particles go along the wire at random, this often each second on averageChance Test: 2 per secondDelete: at 1.5 s, give or take 0.5. Remove particles at an age (since birth, or since entering this event), or at onceDelete: at 1.5 s, give or take 0…InSparkleColour: white. Set the colour of particles entering the eventColour: whiteScale: × 2. Set the size of particles entering the eventScale: × 2Delete: at 0.15 s since entering. Remove particles at an age (since birth, or since entering this event), or at onceDelete: at 0.15 s since enteringIn
Magic dust: born round the wand's tip, drifting up; now and then one flares white and is gone.BirthForcesPhysicsLooksTests
  • The wand tip can be an object parented to the wand: it's followed wherever it goes. Inherit Motion passes a little of its motion on, so the dust streams after it.
  • A negative Gravity makes the dust rise.
  • The Chance Test sends each particle to Sparkle twice a second on average, at random, so they twinkle one by one.

The settings that matter

  • How many are alive is about the birth rate times how long each lives: 2000 a frame, living 0.8 s at 24 frames a second, is some 38,000. Shorter lives are the cheapest way to fewer particles.
  • Speed and Spread: Speed sends them all one way, Spread adds a random push any way. A burst with Speed 0 and a big Spread goes out evenly.
  • Drag takes speed off, so sparks slow and hang. More Drag, shorter flight.
  • Colour: a fixed colour with a little Variation, in the sidebar or by a Colour in a flow. A colour above 1 glows brighter in the default material, which suits sparks.

What goes wrong

  • The bake is slow or the viewport crawls. Too many alive at once: cut the rate or the life, and set the Display panel's Viewport Share to 0.1 while you work. Renders still show them all.
  • They look like dots, not streaks. Turn on motion blur, or Trails.
  • Render Multiply's copies sink into the floor. They don't collide: keep its Spread small near floors and walls.
  • Nothing happens after the burst. The event Spawn sends to needs its own forces: Gravity and Drag don't carry over from the event before.

Shot ideas

Ideas for what to make with VecFlow and how to make each one in Blender: a bird on fire, a dragon's breath, smoke paths, rocket exhaust, magic trails, pours, flags and things that break.

Snow, rain and confetti

Things that fall through the air: snow drifting in the wind, rain streaking down and splashing, confetti tumbling in many colours.

On this page

Start fromGrinder sparksFireworksDust in a sunbeamA trail of magicThe settings that matterWhat goes wrongRelated