Particle Trail Length

How-To
1

I’m trying to create a particle with a very long trail. from the docs I should be able to increase the time via one of the trail fade modes and increase the time. however I get some unexpected behavior.

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Increasing the trail decay to 1 just seems to keep the trail at the same length oddly… but then when particle dies now the trail will just hold there for an additional second before fading out which just looks odd cause the trail then look frozen in space for a second.

How to make really long particle trails, like trails that happen for many seconds long?

2

Well, there are some caps in place on some of the properties the Trail Emitter for performance reasons, but theres a few things you can do to make trails longer.
The most unrestricted mode is the geometry mode and you can accomplish something like this:

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Thanks,
-Jani

3

That’s pretty disappointing news. Those trails even using geometry method are still not even close to long enough.

IMO there should be a user control, I understand the need for performance caps but the user should have some better controls here. What if the user only has a very low amount of particles, the trails should be able to be longer given less particles = longer trails per particle right using the same memory? also all systems are not the same so if you have a better graphics card shouldn’t you be able to max your particular systems performance? Also there could be reasons why take it out of real time mode to pre-render and element in which case the performance constraints would not be the same limitation.

Anyone ever built a custom trail shader to get around this limitation?

4

Hey Bradon,

Try this scene. I don’t know how long the particles will last, because I got bored of waiting for them to stop drawing trails.

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Main things in this scene:

  • Low Max Particle Count (this frees up more space for more trails)
  • Really Large Num Trail Vertices (this sets the number of points per trail)
  • Really High Fade Age (this stops when the particles begin to fade out or scale down)
  • Really Long Particle Life Span (keep the particles being generated)
  • Locked 30 FPS (new points are generated every frame, so less frames means longer trails)
  • Control Point Spacing (sets the minimum distance between a point and a new point)

If this somehow still isn’t enough, The node trail node can be used with an extruded spline, which can be set up for ridiculously long trails too.

StupidLongParticleTrails.dfx (70.7 KB)

Thanks,

Ryan

1 Like
5

Fantastic! It can be done!

Thanks once again Ryan for the clear example.

I also would love a widget to control the taper as a nicer user input as described in this post:

One last question, is there a debug mode which will show only the trail vertex, and control points that are generated rather than the extruded line? also something like show metrics on the particle root node that gets data from the particle trail?

I’m always looking to access or view the intermediate data, its helpful for debug. I’m catching a little bit of line wiggle on the trails, could be the normals on the extruded geo, but would be cool to see the control points to verify whats happening.