Wisps with particle trails

[Dragofer 1430]

I'd like to get this kind of wisp ingame:

Putting a glowing ball on a spline was straightforward enough, but I haven't been able to get it to leave a trail of particles along its path. My 2 first attempts went like this:

1. Make an additional func_emitter for the trail particle and bind it to the spline's mover -> the trail particle spins insanely fast. This is an old & frequently encountered bug when binding particles to something.
2. Make an additional light which has the trail particle as its model and bind it to the spline's mover -> the trail particle always maintains its starting orientation and doesn't leave a trail.

Then I found out that the fire elemental leaves a particle trail like in the screenshot. But it looks like this was a very custom solution: the elemental doesn't def_attach its trail particle, tdm_elemental_smoke.prt, but rather has these 2 spawnargs that only seem to work on the elemental:

"smokeParticleSystem1" "tdm_elemental_smoke-body"
"smokeParticleSystem2" "tdm_elemental_smoke-body"

Maybe there's some way to adapt these "smokeParticleSystems" to non-AI entities like a light or func_emitter? Or another approach altogether?

[Dragofer 1430]

Alright, looks like I found the solution: besides patches and func_emitters there exists a 3rd method for generating particles: func_smoke entities. Like scripts, they produce particles that exist in the world independently of any entity, so they'll stay where they were made regardless of where the func_smoke goes afterwards. Based on preliminary tests it seems to do what I need perfectly.

Wiki: World Particle System