Resolved Raycast on a Rigidbody stops working after over an hour of play time

So, as the title says, I'm running into an issue where raycasting onto a rigidbody object seems to stop working after over an hour (I don't have an exact number) of play time.

Context:

I have some interactable items (gameobjects) with Rigidbodies on them. I raycast to check if the player is looking at them, and will display some text that displays the item's name. The player can then use the LMB to pick up the item.

However, I've run into an issue where after over an hour of playtime the raycast on these items stops working.

I've done some experimenting in the Editor, and noticed the following -- after the raycast stops working:

• If I remove the Rigidbody entirely, the raycast will work correctly
• If I disable + re-enable the Box Collider on the item, then the raycast will temporarily work for a few seconds, before it stops working again
• I have some code which sets the Rigidbody to be Kinematic (and Use Gravity = false), however this doesn't fix the issue
• I can re-create the issue by setting the Time.scale = 100, and waiting around for a few minutes... so replication at least isn't completely painful

I'm kind of not sure the best way to proceed for solving this issue. Maintaining the Rigidbody + Raycast is vital to the game's experience.

Is this an issue someone else has run into before? Is there some physics settings that might fix this? Or is this going to be a complex issue to solve?

EDIT: I am using Unity 2021.3.4f1, if that's useful at all.

Appreciate any help or advice!

 

I'll guess the rigidbody is going to sleep. This occurs with inactive rigidbodies to save cpu. You can force it to wake up with https://docs.unity3d.com/ScriptReference/Rigidbody.WakeUp.html I think (not confirmed) you can stop it sleeping with https://docs.unity3d.com/ScriptReference/Rigidbody-sleepThreshold.html = 0

 

Thanks for the suggestion! Unfortunately, I played around with the WakeUp function and sleep threshold, and it did not seem to fix the issue.

Even if the Rigidbody is in the "Awake" sleep state, the Raycast continues to ignore the Rigidbody. Calling WakeUp after the Raycast issue occurs also didn't fix the issue, etc.

I have a few things with the Physics settings I'm going to explore, then I may have to just try replicating in a blank project/empty scene to confirm if maybe it's a plugin or some stray bit of code causing this.

 

Ah, I'm sorry, that was all I could think of. Hopefully someone else can help!

 

No worries! Appreciate the help regardless!

 

As an update, I think I have found the actual cause of the issue:

There were 2 or 3 Rigidbodies in the scene which were displaying this warning beneath the Transform if viewed on the inspector:

"Due to floating-point precision limitations, it is recommended to bring the world coordinates of the GameObject within a smaller range"

If I set these to kinematic, and change the transform position (so they are within floating-point limitations) then Raycasting onto Rigidbodies works successfully for *all* Rigidbodies.

Currently just working on a solution for auto-detecting and correcting any floating-point issues.

I'll update this thread if I think the solution I come up with is useful.

This might just be a hyper-specific issue on my end, but hopefully it can help someone else!

 

Okay, just leaving this additional info here in case it helps anyone else:

As it turns out, there were 3 Rigidbodies which had managed to fall out of the map. As a result, they just kept falling forever, where eventually their Y axis on the transform would end up causing an issue with floating-point precision.

I actually had already created a script which checked for if "Items" fell out of bounds, however, the Rigidbodies which fell off the map were *not* "Items", so my script wasn't considering these specific Rigidbodies.

I've updated my script so it can keep track of *all* Rigidbodies, so if they fall out of map, they'll respawn at their origin and have their Rigidbody set to be Kinematic.

My solution might not work for everyone (ie: maybe Kinematic needs to be off in someone else's project), but it seems to work fine for me!

Hopefully that helps anyone else running into a similar issue.

 

Thanks, @leeham9 , it appears I had some blood splatter escaping the map and falling endlessly because they never hit anything. Which made my normal shooting ray casts go through enemies. Wow. Thanks.

I never had any warnings pop up in the console feed. The only warning appearing is if I actually select the objects in the inspector.