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High ParticlePerStripCount messy

Discussion in 'Visual Effect Graph' started by Crouching-Tuna, Feb 17, 2020.

  1. Crouching-Tuna

    Crouching-Tuna

    Joined:
    Apr 4, 2014
    Posts:
    82
    Hi. I'm just trying to create a long labyrinth of spiral, for example. But the long chain of single strip is not really predictable. It has a chance to skip points, break up the strip even if i already set StripCapacity to 1, and randomly decides to start/connecting from elsewhere

    I also attached the vfx (it's basically particleId into SequentialCircle, and offsetting the Z also based on particleId)

    Expected result: long unbroken chain spiral from front to back

    Also try with low "Num" and replay the graph. It only starts doing this, sometimes around 37, sometimes 41, sometimes 70+. (By "sometimes", i mean it has to be replayed many times).
    The higher it is, the more chance it'll break

    Note: the attached vfx has a StripCapacity of 2. But it shouldn't matter

    Cheers
     

    Attached Files:

    Crouching-Tuna, Feb 17, 2020
    #1

  2. JulienF_Unity

    JulienF_Unity

    Unity Technologies

    Joined:
    Dec 17, 2015
    Posts:
    326
    Hi,

    Strips is still an experimental feature in VFX Graph, so it still misses lots of high level helpers and warning/error feedbacks.

    2 things to know:
    • You shouldn't use particleID and spawnIndex in other places than stripIndex port because it is not guaranteed to be deterministic with the actual index of the particle in its strip. So while it is fine to use them to set the current strip of the particle, once the strip index is set you should use particleIndexInStrip and spawnIndexInStrip to position your particles in a deterministic way.
    • Quad strips may break at some point when some points overlapped. Because in that case the tangents of the particle cannot be computed correctly.
    Those are things that will be improved in the future. But at the moment you need to be aware of these low level limitations.
     
    JulienF_Unity, Feb 17, 2020
    #2
    daneobyrd and cAyouMontreal like this.

  3. cAyouMontreal

    cAyouMontreal

    Joined:
    Jun 30, 2011
    Posts:
    315
    @JulienF_Unity this is very useful!! We struggled finding a way to make strips work correctly with burst spawning (no issues with constant spawning). Thank you!
     
    cAyouMontreal, Feb 24, 2020
    #3