StaticMesh doesn't register hits if not a root component

[antidotcb]

Unreal Engine version: Version: 5.3.2-29314046+++UE5+Release-5.3
I have created two Bullet blueprints.

First one has following structure of Components:

It has simple Blueprint graph:

and following Collision settings on a Static Mesh component:

it works as expected:

• fly and chases player
• it register hits with geometry
• damages the actor it hits
• destroy itself after this

Everything is OK, but it doesn’t allow me to rotate the Static Mesh model, as it has only scale in Transform:

So I created a second blueprint, almost everything is the same, but with slight difference:
Root Component is not a Static Mesh Component, but a DefaultSceneRoot

Everything else is exactly the same.

The expected results are never achieved:

New BP doesn’t register hits with not moving objects.

• It doesn’t register hits with statically located geometry on level (flight through it)
• It pushes a player and never triggers a hit event if player is standing still player.

The only case it register hits is the Player is moving towards a bullet.

The only good thing is that a bullet now properly oriented as I rotated a static mesh as it has transformation now.

• Can someone tell me what is the root cause of such unexpected behavior?
• Why it never registers hits when anything but a static mesh is root component?
• Why it only register hits with moving objects and not statics?

[ClockworkOcean]

I’m pretty sure this is how it works.

I can’t find the article right now, but I saw somebody saying as much recently…

Here’s a couple of ( old ) self referring articles about it

Collision Component MUST be placed in root

See this topic: Bouncing projectiles have no collision - World Creation - Unreal Engine Forums This is such weird behavior + so bothersome when using inheritance that I assume that this is a bug. I mean we have like dozens of collision-settings but not adding a random collision-component (doesn’t even have to be the one you will be using) as the root will break ALL collision-checking for this object except for pawns. Reproducible.

And another

Sweep only works with Root component?

Days of work to isolate that issue. Title says it all, Sweep on Set Actor Location or Add Offset will work on ROOT component ONLY!! That’s quite terrible, my BP is composed of multiple StaticMeshes, and only root will collide with player (very fast moving object). Am I doing my setup wrong? Is there an option i’m unware of? Or is it by design (if so, a note on sweep tooltip would have been much appreciated) Thanks

But I have this more recently also…

[antidotcb]

What I in the end to resolve the issue:

• set root component to StaticMeshComponent with simple collision as simple sphere around my bullet mesh
• set root Mesh to invisible
• added another StaticMeshComponent attached to root component, with my Bullet mesh, and transformed it as I needed (I could rotate it!)

Seems to be working for me now. Still wasting some memory, but bullets are fast to disappear, so I don’t bother too much.

Solution with collision shpere as root didn’t worked for me - it STOP near wall, but never register a hit

[antidotcb]

I made a new version, from scratch.
Used SphereCollision as a root, and a StaticMesh on top of it, and it finally started working.
I don’t know why my old blueprints weren’t working this way, but now I’m happy.
Thank you.

P.S. I tried to use ProjectileMovementComponent.SetUpdatedComponent(StaticMeshComponent) but it didn’t worked for either, when it’s inside components hierarchy and is not a root component.

[ClockworkOcean]

I think it’s like someone mentioned in one of those threads, you can’t be checking a whole list of components every tick