Geometry Collection loses collision after breaking/fracturing. [Chaos Destruction]

[Eight_P]

I have been recently looking into Chaos destruction with 5.7 and encountered numerous scenarios of Geometry Collections losing their collision (at runtime) in unexpected (and hopefully unintended) ways.

The issue seems to occur when the first breaking/fracturing damage to an intact GC is not causing any further internal damage (or so).
Probably better explained by these examples:

A GC with level 2 bones breaking into the level 1 clusters but not breaking the level 2 connections due to disabled “damage from collision”:

It can also be replicated with a two-level GC set to static/kinematic on the actor object type.

However, it seems to only happen on the “first hit” to the GC.

Which can also be shown when setting some of the bones in a cluster to static/kinematic.

This is all done using Apply External Strain + Apply Breaking Linear Velocity (radius: 1, propagation depth: 0), but I also found the same behavior using the default FS_MasterField.

I’m just hoping for someone smart to see this and shed some light on it.
Thank you.

[Braen]

I have a similar problem: the collision disappears after deleting a shard.
If I split the plane into one level (without clusters) and set the lifetime (removal-on-break) to zero or slightly higher, then after the Geometry shards disappear, the collection stops responding to the check and the collision disappears. It’s as if the actor has disappeared from the world, but continues to render.

[Eight_P]

Just to add, the GC also losses collision when using removal on break or sleep after the pieces have been removed.

[TetraStudiosDev (TetraStudios)]

@Braen @Eight_P Did you ever find the solution to this? Having the exact same issue.

[TetraStudiosDev (TetraStudios)]

I’ve been able to find a solution - ensure BOTH SleepMinMax and RemovalDuration are set below 1. As well, remove any Initialisation Fields (ie anchor fields) attached to your collection. You can set “Anchored” on the pieces instead. The system will not work otherwise.

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Hello, Kyle B. Thank you very much for bringing this issue to my attention and for taking the time to respond. I wanted to point out that I was using version 5.7.1 from the launcher. This might be critical. I recorded a video and will attach the code to the message for the Character, which I insert into the video and the project itself. I also don’t use clustering - I only have two levels - 0 and 1 [Attachment Removed]

[Eight_P]

I don’t think there is any solution other than hoping for Epic to see and fix it.
There seems to be a bug report for loss of collision when using removal now.
I fear a bit it ignores that it can also happen without removal, but maybe once they see it, they’ll figure it out.

[YuusakuFujiki]

I tried as you said but it didnt work. GC will lose collision when pieces are removed. Am I doing right?

[KryogenicGames]

strangely i wasnt to reproduce this issue, new gcm collision works even after break, tried various settings but still collision present tested in 5.7.2