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Changes to "Custom simulation space" breaking backwards compatibility?

Discussion in 'Editor & General Support' started by dotsquid, Apr 25, 2019.

  1. dotsquid

    dotsquid

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    At first I sent this message to @richardkettlewell directly via private messages but he asked to make it public, so here it is.

    We've recently updated our project form 2017.1.4. to 2018.3.12 (yeah... there were some issues with the versions in between) and everything was great on the first sight. But then I found out that some of the particles are moving with noticeable jitters. Since they use a custom simulation space I'm pretty sure that at some point prior to 2018.3.12 you've changed the moment when that simulation space is taken into account. Specifically, now it's taken into account before LateUpdate, but before that it was done after LateUpdate. I made this conclusion because we're moving the transform used for custom simulation space in LateUpdate.
    I searched through the changelogs but did not find any mentionings about this change.
    I wonder is my guess right and if so what was the reason for doing this major change?
     
  2. richardkettlewell

    richardkettlewell

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    We haven't deliberately changed anything in this area between those versions, but I suspect that this is something to do with Unity's new Transform update system which was implemented during the 2017.x cycle.

    Moving that transform in LateUpdate sounds like a use case we've not encountered before.

    If you could submit a bug report with a minimal reproduction project, and reply here with the case number once you have it, we will be able to investigate further.
     
  3. dotsquid

    dotsquid

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    Hey Richard. Thanks for reply.
    Do you mean I should prepare a project which can be run in both 2017.1.x and 2017.x+ versions and show the difference in behaviors?
     
  4. richardkettlewell

    richardkettlewell

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    It should be enough to submit the 2017.1 project with the explanation that it behaves differently (jitters) once updated to 2018.3. Our QA will then narrow it down more specifically before sending it to me to fix.

    If you also include the forum link in the bug report it will help QA to be able to see this discussion.
     
  5. dotsquid

    dotsquid

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  6. richardkettlewell

    richardkettlewell

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    Hi again,

    We've investigated this and found the bug. Thanks again for reporting it. We will apply the fix in a 2018.4 patch as soon as we can, though it will take a few weeks to make it through our testing/release process.

    (2018.3 patches are about to finish, as we are about to move 2018.3 to LTS status and call it 2018.4. It is basically the same version though)
     
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  7. dotsquid

    dotsquid

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    Great! I'm also looking for a fix for this issue https://fogbugz.unity3d.com/default.asp?1148610_n07dhaqujpnqa3i6 because this one has no sane workarounds.
    Any estimates?
     
  8. richardkettlewell

    richardkettlewell

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    Not yet - we are in the process of landing the current batch of fixes to the release branches. That bug missed the cut - it will be looked at in the next round though :)
     
  9. dotsquid

    dotsquid

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    Then I guess we'll have to wait for 2018.4.2 ;)
     
  10. richardkettlewell

    richardkettlewell

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  11. dotsquid

    dotsquid

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    Great! Thanks.
     
  12. dotsquid

    dotsquid

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    Hi @richardkettlewell! I checked the changelog and it was said that the issue was fixed in 2018.4.4.
    The problem is that it seems it's not really fixed. I checked the project I attached to the bugreport at one time with 2018.4.5 and it indeed looks normally.
    But in our game the problem stayed. I used FrameDebugger and it shows that some particle systems keep using random textures instead of a specified one. Actually, it's not random, but a texture being used for the previous draw call.

    Here are some screenshots:
    upload_2019-8-1_9-45-6.png
    upload_2019-8-1_9-45-14.png

    And here is how it looks in dynamics:
     
  13. richardkettlewell

    richardkettlewell

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    Hey, I'm sorry to hear that it's not fixed for you.
    Are you able to submit a new bug report + repro project that still exhibits the issue?
     
  14. dotsquid

    dotsquid

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    That's the actual problem for me now - I can't reproduce this bug in the minimal project. But I'll take a try again.
     
  15. dotsquid

    dotsquid

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  16. dotsquid

    dotsquid

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    Hi! Any ETA of the fix?
     
  17. richardkettlewell

    richardkettlewell

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    Hey. This issue caused a string of regressions due to a bad fix I made :( :( Sorry about that.

    We’ve actually got a fix en-route that I’m confident is the correct fix to put this issue to rest once and for all! I’m not in the office this week so I can’t advise on which patch number it might land in - it should be landing this week tho, so probably 2 weeks away from being public. If you ping this thread on Monday next week, to remind me (or DM me) I will give you a more accurate update then.

    Sorry again for the bugs!
     
  18. dotsquid

    dotsquid

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    Never mind and don't worry, S*** happens and everyone of us makes bugs from time to time.
    If it's about 2 weeks till the update, I guess it's ok for me, so I'm not going to bother you here :)
     
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  19. richardkettlewell

    richardkettlewell

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    Hey, the fix has made its way into 2019.2.0b4, but a problem prevented it from landing in 2018.4. Hopefully it’ll go in this week though. I’ll update again once I know more.
     
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  20. richardkettlewell

    richardkettlewell

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    Hey again.

    The fix has landed in 2018.4.10f1 (hurrah)

    It should be available to you close to the 26th September, unless QA find anything bad in the patch that delays its release.
     
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  21. dotsquid

    dotsquid

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    Awesome! Thanks for fixing the bug and for giving a heads up.
     
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