Bug / Crash Collisions don't work consistently with multiple solvers in Obi 7

[goldfire]

I never had these issues with Obi 6, but ever since upgrading to Obi 7 I've been tearing my hair out trying to get this to work. I've made a net prefab that uses a grid of ropes to create a net that captures a character that has a sphere obi collider attached to it. There are two of these at different parts of the game that are in different additively loaded scenes. If you load in to either one of these they work fine with collisions working on the obi collider. However, if you trigger the first net and then continue onto the second (which when reached, the prior net's scene has long since unloaded), the collisions don't work.

I'm having the same issue either with the CPU or GPU backend. It's using the async simulation -- sync fixed grinds the game to a crawl, so it's not really an option for this. I've spent hours and hours over multiple days and every change I make either breaks the first one or the second one, I can't ever get them both to work consistently. Any thoughts on what could be happening?

Unity Version: 2022.3.57 (built-in renderer)

[josemendez]

Hi,

The collision detection pipeline hasn't changed at all between Obi 6 and Obi 7, so behavior should be no different. Would it be possible for you to send your project (or a smaller one that reproduces the same issue) to support(at)virtualmethodstudio.com so that we can take a closer look at it?

kind regards,

[goldfire]

Hi,

The collision detection pipeline hasn't changed at all between Obi 6 and Obi 7, so behavior should be no different. Would it be possible for you to send your project (or a smaller one that reproduces the same issue) to support(at)virtualmethodstudio.com so that we can take a closer look at it?

kind regards,

It's quite a massive game, so sending the project isn't possible. I'll try to put together a test case, but it's going to take a fair amount of work to do that and no guarantees it replicates the issue. Is there anything I can test in terms of maybe trying to reset the physics state or something like that in the meantime? I suppose it's possible this was an issue before and we just never caught it until after the upgrade since we've been doing a lot more full game QA testing recently.

[chenji]

Random guess:

1. Check whether the second net is correctly set Obi (Obi Collider config, whether put in the correct solver, etc), rigidbody, unity collider's setting. You may compare its settings vs the first one, to check whether there are any differences, when playing the game. 
   
2. Check whether "Auto sync transforms" is unchecked in Unity's setting. It may result in weird physics behavior.
   
3. It's different that Collision does not work at all v.s. Actually it works but visually you cannot see the collision behavior (usually caused by high speed object). Try enbable Dynamic Collision Detection in player's Rigidbody to see whether it works. Possibly your player's speed is high when reaches the second net, which gives you illusion that it's a problem related to load/unload