I've been experimenting with particle thrusters a lot, without that much success. Now I realized why. Looking at KSP's thruster particles, and at actual exhaust physics, brought me a realization of how to do particles properly. Then I found I can't do that in FSO.
The idea is that particles represent gases at high velocity. As such, their speed should be similar to the engine's exhaust velocity. That would be something near 3000m/s for a realistic engine, meaning an individual particle would have to have something like 0.001s lifetime to give a 3m trail. While this is a bit excessive (and probably wouldn't work), but the point is, you've got short-living, fast particles. You don't even need lots of them, obviously there'd be a lot per second, but they'd have much shorter lifetime.
So, here's my request:
Allow single-bitmap thruster particles, like for missile trails. Animated ones are not good for what I want to do, they could be used, but it'd seem hacky.
Allow control over lifetime and velocity range of thruster particles. Velocity range would work such that at max throttle, you get max velocity, and at zero (or negative) throttle, you get minimum velocity.
Allow defining "end radius". The particle would shrink to it from the start radius. Would go well with otherwise static particles, but probably isn't very important in the end.
That would allow particle thrusters to compete with modeled ones and with thruster bitmaps, both performance-wise (a small amount of static particles instead of large amount of animated ones) and visual-wise (they'd look like thruster flames, not like smoke trails). They'd look good on fast ships, too. All that without a performance-intensive script (I know there's one, I also know overuse can and will bog down the game). I'd also allow more options for thruster particles, which is good, because they're currently woefully limited on what they can do.
