Attached actor causing Crash

I have a reliable crash whenever a player character, holding onto a dynamic actor, performs any kind of quick movement.

Since i mean for the actor to be maneuvered around the environment, I disable the physics and collision and attach it to the player character for transport about the environment. The crash seems to be collision related - as the log gives me a warning and using complex collision seems to fix the problem:

[2014.12.12-05.38.44:325][237]LogPhysics:Warning: PHYSX: …\PhysXExtensions\src\ExtRigidBodyExt.cpp (234) 4 : computeMassAndInertia: Dynamic actor with illegal collision shapes
[2014.12.12-05.38.44:325][237]LogPhysics:Warning: PHYSX: …\PhysXExtensions\src\ExtRigidBodyExt.cpp (283) 4 : PxRigidBodyExt::updateMassAndInertia: Mass and inertia computation failed, setting mass to 1 and inertia to (1,1,1)

The collision I want to use is the box simplified collision that one can add to the static mesh and I don’t understand why this would cause a problem. Also, I would prefer to not use complex collision since i expect that is expensive.

Thank you greatly for any help!


Hi rosenkranz,

Could you post your full Callstack, Crash Logs and Dmp file? Directions on where to find all of this info are in the link below.

Also, how are you attaching the object to the player? Feel free to post additional screenshots if you like.


Branch: This is a binary build from the launcher

Build version: 4.6.0-2369412

Detailed description of the issue:

I believe the project uses default settings and I submitted the crash report, below is the callstack. I have also attached a screenshot of the blueprint where i attach the actor.


We apologize for the inconvenience.
Please send this crash report to help improve our software.

Screenshots/Link to video: Ill see about trying to capture a video this evening if it would help.

Repro Steps

Action 1 “Play” game on any level with some complexity

Action 2 use player tractor beam to grab a dynamic actor

Action 3 rotate the camera suddenly, using the mouse, or jump. Unreal will crash 100%.

System Specs: dxdiag attached

btw, i had to tack a .txt onto the dmp file to get it to upload

Thank you!

If its of any help I uploaded a video as well, though i’m not sure how much help it would be as it shows the scene working more than the crash.

The video ends when I try a rapid movement and unreal crashes causing it to seemin

Could you provide some screenshots of the blueprint setup you’re using to pick up the object? I have this Physics Handle setup in my testbed but no matter how fast I move objects around I don’t receive a crash.

Also, it looks like your callstack and logs didn’t upload with your previous post. Try zipping them before you attach.

Ill definitely give that tutorial a go, I haven’t seen this before and it handles things in a very different manner.

In the meantime, I’ve attached more of my blueprints and the logs in zip form.

Of interest: I’ve discovered that disabling collision before attaching the component (and re-enabling collision when i detach it) seems to fix the issue. Unfortunately, this isn’t practical since i can then force the object through the environment while its being held but it is perhaps diagnostically useful.

Thank you!

[link text][1]

I haven’t been able to reproduce your setup yet. It looks like you are using a Tractor Beam ‘Mesh’ attached to the character and these functions use the overlap info with physics objects, correct? Also, how are you triggering the functions in the Eventgraph?

tractor beam and tractor origin are capsule components that i use to determine what can be ‘grabbed’ and where to go respectively (They are the volumes that you see in the ingame screenshots.) They are attached to a tick event that will activate only if nothing is grabbed at the moment and i activate the beam by disabling or enabling the collision on ‘tractor beam’.

Attached is the event graph setup, I based the entire thing off of the spaceship/ufo from the content examples.

Using the physics handles instead of the attach feature worked brilliantly, thank you for the pointer and putting together so thorough a tutorial!

You’re welcome, I’m just glad you got something that works for you. Good luck with the rest of your project.