Bug / Crash Burst not working at all

[josemendez]

The freeze can be reproduced by:
 1. Set your rope with Burst backend.
 2. Add an empty game object with OniColliderWorld
 3. run this

The forever freeze happens when "Oni.UpdateColliderGrid();" is called in it.
I mean sure, why would you add OniColliderWorld manually. 
But then it doesnt matter, it neednt freeze.

Thanks for reporting! I will try to reproduce this. We're about to release an update in a bout a week or so, will see if I can squeeze the fix in.

On another topic:
How come my FPS is super low when running Burst backend in build, but it is fine in editor?

Unity: 2019.4.12f
Obi: 5.6
Burst 1.3.6
Collections: 0.9.0 preview 6
Jobs 0.2.10 preview 12

This is called death spiraling (aka well of despair, fixed timestep spiral, and many other names). It has been discussed in this forum a lot. We even have a video on it:
https://www.youtube.com/watch?v=sUVqa-72-Ms

Basically, this is an inherent limitation of the fixed timestep scheme used by Unity and many other game engines. Physics steps have a fixed duration in seconds. If a frame takes a long time to render for whatever reason (including physics calculation itself), to keep up with rendering it might not be enough to simulate physics just once during the next frame. Two, three or more physics updates might be necessary in a single frame. Updating physics isn't free though, so this might make the current frame to take even longer to render than the previous one, worsening the situation. This causes a downwards performance loop that will only stop once you reach Unity's max fixed timestep setting. However the game might not be able to recover from it at this point. The hallmark of death spiraling is FixedUpdate() appearing more than once per frame in the profiler, just like in your pic (x10). This means physics are being updated ten times per frame, which will bring performance down to a crawl.

Long story short: use a longer timestep or reduce your max fixed timestep.

As to why there's a difference in Burst performance in editor vs standalone of a single FixedUpdate() call, it's hard to tell. There shouldn't be any at all, as long as Burst is enabled (and supported) in your target platform. See: https://docs.unity3d.com/Packages/com.un...er-support

It also goes without saying that if your target hardware isn't as powerful as your desktop computer (for instance, if you're building for iOS or Android), performance there won't be as good as performance in the editor.