Capsule collision replication issue

If you increase the “Capsule Half Height” size of a “Capsule Component” of a “Character” class and start a multiplayer game then the other clients could easily get unaccurate (jittery) collision if they are colliding against meshes with convex or box collision.

How to reproduce:
Create a blank third person template and change the “Capsule Half Height” size to 170 in the default ThirdPersonCharacter blueprint. Start a multiplayer game with 2 clients. Run around (and collide) with the “1M_Cube_Chamfer” mesh of the ThirdPersonExampleMap - especially the corners. Don’t jump. Don’t take the stairs.

Result (screenshot):

Optional for easier debugging: Make the capsule visible in game and move the skeletal mesh of the characters BP to the bottom of the capsule.

The issue happens if you collide with static meshes with convex or box collision. A tiny 0.5m sphere gives better collision (without jittering) than the edge of an 1.5m cube.

Hi Neutronux,

I was unable to reproduce the issue following your repro steps. Here are some screen shots of my test:

Please let me know if you spot anything different between my set up and yours. Also, please send your system specs to ensure we are comparing on the same or similar system.

Thanks,

.

Your setup looks good and I’m testing on 64bit/PCD3D_SM5 as well. I’ve tested on 3 different machines and even on 3 different UE4 engine versions. I’ve recreated a fresh clean project from scratch on each machine today. Third person Blueprint - Desktop/Mobile - Maximum Quality - No starter content - Capsule size in Third Person blueprint changed to 170. Just run straight to the cube and collide at the sharp edge. I’ve tested on following machines:

1st PC: UE 4.14.3 - Win10 64bit - CoreI7 - GTX 1070

2nd PC: UE 4.13.2 - Win10 64bit - CoreI5 - GTX 960

3rd PC: UE 4.12.5 - Win10 64bit - CoreI7 - Laptop

It’s 100% reproducable within seconds. I was able to let them float on all machines within a few seconds.

Your screenshot shows you are colliding about 90° against the flat side of the cube. Please try at the sharp corner like I did in the screenshots and keep your eyes on the other client all the time while colliding. It only “jitters” for a short moment and if it jitters and you stop movement it’s easy to let him float (espesially on the cube that’s in the default third person map). It’s a bit more difficult to float but very easy to jitter on a fresh cube (drag and drop in map) as well (as shown in the 4.13.2 screenshot).

This screenshots was taken today from 3 different PCs (no special setup - just default Third Person blueprint):

Just as further info: I’ve tried to reproduce this bug now additionally with UE4 4.10.4. It’s still not perfect but better with 4.10.4 - He jitters similar like in the other engine versions but much faster/quicker and never gets to the jump-loop so his capsule was never that long in the air from the view of the second client (only jump-start very short time). Even after playing around for about 15 minutes on the edges from the cube I was not able to let him float like in the previous posted screenshots for 4.12-4.14 just through collission on 4.10.4 (and I tried hard :slight_smile: ). I’ve retried afterwards again on the same machine with UE4 4.14.3 and was able to let him float within seconds (without jumping ofc) just through collision on the sharp edge.

Thanks for the all the comprehensive repro steps… I have reproduced the issue and logged it as UE-40420 which you can track on the following link: Unreal Engine Issues. Please be aware that since the issue must be reviewed and prioritized by our development staff, it may be a while before it can be addressed.

-.

Hey Neutronux how have solved this problem, can show me BP?