Currently, the generation of thruster particles is inconsistent.
They are always spawned when in external camera mode (screenshot mode).
However, when in first-person (ie. actually playing), there seems to be a very strange set of rules that determine whether thruster particles are spawned or not which seems to depend on the relative direction of the player's ship and the normal of the thruster, which results in inconsistent generation of particles.
Maybe this is some performance-related thing to prevent generation of "unnecessary" particles, but looks really really dumb when something flies past and then the particle trail suddenly appears as if it only turned on its engines then and there.
And it looks exceptionally retarded when you're using thruster particles for a "re-entry" effect and the smoke isn't generated from certain angles.
So I hereby request that thrusters particles be generated forever and always, just like how it is when you're in free/external camera.

You can imagine how stupid this would look if the thruster particles didn't generate from certain angles making it look like its a rocket that's firing its boosters downwards from time to time and not something ablating its heat shield (in an exaggerated fashion) during re-entry...