Vapour Trail Experiments

It’s Sunday, so I’m allowed to work on things that aren’t important. This started as a test for an idea I have of how to create a ‘wake’ that expands behind you, something I ultimately want to use to cut through some layers of cloud as you fly. But I accidentally made a cooler version of the existing contrail, so I tried randomly colouring it, and here we are.

Not sure what to do with it from here. I like everything about it except the end, it has what I call ‘fat tail’ problem: no matter how gently I tell the alpha to fade out, the final, big chunk of vapour always looks like it ends rather suddenly, like your ship just has this big fat tail following it.

I like the idea that breacher ships of different factions would have different contrail colours, though. And I think engine upgrades will probably affect this too.

Here are a million shots:

Vapour Trail Tests 01

Vapour Trail Tests 02

Vapour Trail Tests 03

Vapour Trail Tests 04

Vapour Trail Tests 06

Vapour Trail Tests 07

Vapour Trail Tests 08

Vapour Trail Tests 09

Vapour Trail Tests 10

Vapour Trail Tests 11

Vapour Trail Tests 201

Vapour Trail Tests 202

Vapour Trail Tests 203

Vapour Trail Tests 204

Vapour Trail Tests 205

Vapour Trail Tests 206

Vapour Trail Tests 207

Vapour Trail Tests 208

Vapour Trail Tests 211

15 Replies to “Vapour Trail Experiments”

  1. Since those are stills, it looks like there is depth (you can move on the Z direction). It looks really good.

  2. Would exponential decay (rather than linear decay) of the opacity of the trail solve the ‘fat tail’ problem?

  3. Undoubtedly we’re hours behind the times but my first thought is that you need to take down the brightness first, faster or both than the alpha – let the abstract plasma cool and become something else before it disperses.

  4. I’d experiment with different functions for fadeout speed (Chris mentioned exponential). You could also try having the tail particles wander a bit to break it up.

  5. it looks like you have too many particles drawn over each other. the bigger they get, the more of them will overlap, since I’m guessing you’re generating them at fixed intervals so it looks good at a small scale.

    then at the end of their lives, you’ll have some 100 particles at, say, 5% opacity overlapping, which still gives it a pretty solid look.

    Try experimenting with a random lifespan, i.e. if your particles currently all live for 10 seconds make the particles die anywhere between 5 and 10 seconds instead. That way you’ll only have a small number left at the end of the trail and should have a much softer look.


  6. Contrails don’t just fade, they break up. Try scattering the particles and/or adding Perlin Noise to the alpha if possible.

  7. I like the idea of particles having a random lifetime as opposed to just fading out. That way, the tail itself would vary and be more visually interesting, and it would (hopefully) make it seem more natural. Of course, it could also look like crap. You don’t know until you try!

  8. Is there a way to have a different entity of ‘vapour residue’ for instance, which appears wherever the vapour trail has been?

  9. Maybe give the particles a finite decay life down to a certain size/opacity that’re really small and faint but long lasting so that single pixlewidth end of the cone is really long.

    That way you’ll leave a bit of a trail all through space with your plasma (to a point, ain’t nobody want forever trails)!

  10. There’s some really good thoughts from the folks above on the technical aspects of the vapour/contrails.

    The only thing I can do is wonder if a few of the NPCs in the Heat Signature Universe believe that they are linked to some sort of chemtrail conspiracy!

  11. Couldn’t you have the trail shrink as it ends it’s lifetime? That combined with the alpha would make it look “better” at least in my head.

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