Quick answer: On the sub-emitter, set the Inherit option in the Sub Emitters module to include Velocity (or use the Inherit Velocity module), so spawned particles carry the parent particle’s motion.
A rocket trail sub-emitter spawns smoke puffs, but they hang in place instead of trailing behind the moving rocket particle. Velocity wasn’t inherited.
Sub Emitters Module Inherit Flags
In the parent system’s Sub Emitters module, each sub-emitter entry has an Inherit dropdown. Enable the properties you want passed down — Velocity, Color, Size, etc. Velocity is what makes puffs trail.
Or the Inherit Velocity Module
On the sub-emitter system itself, enable the Inherit Velocity module:
- Mode: Current — uses the emitter’s velocity at spawn time. Good for trails.
- Mode: Initial — uses the velocity at the emitter’s birth. Good for one-shot bursts.
- Multiplier curve — scale how much velocity carries over.
Simulation Space
Inherited velocity behaves correctly with World simulation space. In Local space the parent’s movement is already baked into the transform, so inheritance can double-count — pick one model.
Verifying
Fire the rocket. Smoke puffs spawn with the rocket’s velocity and trail behind naturally. A stationary emitter spawns puffs that don’t drift.
“Sub-emitters don’t inherit motion by default. Turn on Velocity inheritance, mode Current for trails.”
For projectile trails, a multiplier curve under 1.0 looks more natural — the puffs slow down relative to the projectile as they age.