Blueprint Communication Example 3.2 Problem

Branch: Binary
Build version: 4.0.1-2027741+++depot+UE4-Releases+4.0
Interval: Happens 100% of the time.

Problem Description:
On Example 3.2, chain moves up and down by itself with or without interactivity. I think it has something to do with the physics.

Reproduction: Load Blueprint_Communication.umap, Click Play, Go to Example 3.2 (The pull chain example.)
link text

Attachments List:
Picture showing example attached, DxDiag.txt file attached.

Hello,

I have looked into this project and I see that the handle and chain jiggle a bit, even without being touched. Is this what you are seeing or is the chain going all the way up and down? Could you provide a video?

Thank you!

Yes the chain jiggles, so it’s processing or there’s a physical interaction happening by default, my thoughts are if there were a lot of items like that perhaps it may impact performance. I think it’s physics related. Here’s the video: - YouTube

That is similar to what I am seeing. The jiggle is a little more pronounced on your video than what I get, but the jiggling is just because the chain starts Awake with physics. The Chain’s physics constraints could use adjusting to make that stop completely, but otherwise it is behaving as expected.

my thoughts are if there were a lot of items like that perhaps it may impact performance

If you have a lot of them it will definitely impact your performance. The more physics bodies you have in a scene, the more it will take to process. On a modern system you should be safe have a lot of these chains before the impact is noticeable. This is true for all physics bodies.

Cheers!