Drag
Slow particles to the speed of the air, and blow them along with a wind: for snow, dust, smoke-like drift and settling sparks.
Slow particles to the speed of the air, which moves with the wind.
- Add it
- EventAdd OperatorForcesDrag
- 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
- Light things: snow, ash, dust, confetti and feathers fall slowly and drift. Give them a high Amount: the Snow starter uses 8, Confetti 1.8.
- Sparks and debris that slow down after a burst: a low Amount (0.1 to 0.5).
- Wind: everything with Drag drifts with the air. Set Wind to the air's velocity.
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.
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.
Amount is the share of their speed, relative to the air, lost each second. At 0.15 a spark keeps most of its speed for a while. Under Gravity, particles fall no faster than 9.81 divided by the Amount, in metres a second: about 1.2 m/s at 8, a snowflake's drift.
Wind is how the air moves, in metres a second along X, Y and Z. Particles with Drag come to move with it: the higher the Amount, the sooner. Keyframe it for gusts.
Works with
- Gravity: with Drag, falling things reach a top speed instead of falling faster and faster.
- Turbulence for swirling drift.
- Influence: a value can make some particles lighter than others.
Problems you may see
The editor raises no problems of its own for Drag.