Sweep only takes one collision primitve into account

When you use sweep with an mesh that has multiple collision primitives only one is used for the sweep test.
affected versions: 4.21 and 4.21.1

works as expected in 4.20.3 and below

This bug is very anoying as we rely on correct sweep detection, because we have a lot of objects with multiple collsion primitives which now we spawn inside of walls.

Howto reproduce:
just take one static mesh and setup the simple collsion to use 2 box collision one for the upper half and one for the lower half.

Now create a blueprint actor which has this static mesh as root and add the blueprint node like in the screenshot

Place this acotor a bit floating over the ground and press play in editor
after 2 secs. the object will go halfway in the ground.
If its not working the first time swap the locaion of both collision primitives in the static mesh, as this time the right one was on the bottom.

If you need a simple project to reproduce it please let me know.


We’ve recently made a switch to a new bug reporting method using a more structured form. Please visit the link below for more details and report the issue using the new Bug Submission Form. Feel free to continue to use this thread for community discussion around the issue.



Hi, I have stumbled upon the same issue.

Did you successfully submit a bug? I can’t find a related issue at issues.unrealengine.com to vote for

I did submit a bug report, and recently submitted a sample project.

I submitted one in the meantime as well, also including a sample project. Haven’t heard anything so far, let’s hope something happens now that the holiday season is over…

My Report got added: Unreal Engine Issues and Bug Tracker (UE-67972)
You can vote for it.