Movement Issue (Session 147)


I still have weird tank behavior in my project (4.12.5).
After I noticed this I almost triple checked everything shown in the last videos (I know that not all of my values are the same but it should still work…).
I think I have a mistake somewhere in my BP, but I am unable to find it.

I also made a short video (WQHD, the dropbox webplayer is not working):

Any suggestions?



The cause of that is that there are microdivots in the landscape… and that the track collision mesh has sharp edges.

When two sharp angled surfaces meet each other, and they’re both unmodifiable… the inevitable result is the object itself getting popped up like that to mitigate the forces involved.

Unfortunately, the game doesn’t do the best job of signalling this point.

The easiest way to improve the issue (although it doesn’t fix it completely) is to use a capsule for the tank treads collision mesh, rather than the generated version or a box.

The bigger the capsule, the more forgiving its movement over microdivots. If it’s bigger than the width of the tracks, you can go to the tank itself and set the tracks collision response to world static only, which will make it so that only the terrain can affect or interact with the tracks - which means you can’t get hit in the larger than your track appears capsule.

For further improvements, check out L-Tecs post on suspension system. Which can be tackled after the section IMO - as Ben will still be modifying the movement system before then.


Already guessed that but ignored it since it works in the Session video.
Might depend on the terrain tho (mine is not lowpoly).

Capsules for the track work better; I think I’ll keep it like this.

Yeah… I’m also running a high poly landscape… and those divots still occur for me too. Even on the smoothest glassiest surface I can manage on the height map (even exported it to photoshop so I could paint an area all one color), it still has those issues.

Only completely resolved it afterwards by using the suspension system.

Can confirm the probem is ocurring in my (not lowpoly) project. Running unreal on version 4.15. Capsule colisions did mitigate the issue.

Thanks for this thread. I also have that problem. Putting capsules is a bit better, but I still feel microbumps in the ground regardless…

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