# Character collision/physics weird behaviour (crouch/uncrouch)

**URL:** <https://forums.unrealengine.com/t/character-collision-physics-weird-behaviour-crouch-uncrouch/368726>\
**Category:** World Creation\
**Tags:** crouch, jitter, capsulecomponent, unreal-engine, character-collision, Physics, question\
**Created:** [August 30, 2016, 9:06am UTC](https://forums.unrealengine.com/t/character-collision-physics-weird-behaviour-crouch-uncrouch/368726 "2016-08-30T09:06:37Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![Wrenge](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Wrenge](https://forums.unrealengine.com/u/Wrenge)\
**Post date:** [August 30, 2016, 9:06am UTC](https://forums.unrealengine.com/t/character-collision-physics-weird-behaviour-crouch-uncrouch/368726/1 "2016-08-30T09:06:37Z")

</div>

Whenever I uncrouch on physics object’s ledge that object get pushed. Use Flat Base for Floor Checks didn’t help. Also standing on prop smaller than character’s collision causes jitter. Is it a bug and is there a workaround?

![104893-bug1.gif](https://d3kjluh73b9h9o.cloudfront.net/original/4X/3/2/3/323b58587e11fdab981c82f997e9380486fbe57f.gif)

![104894-bug2.gif](https://d3kjluh73b9h9o.cloudfront.net/original/4X/a/4/7/a47c7a3b2ae48dcf1546c4c2fe75908167eee3d2.gif)

UPD: UE 4.13 Problem still exists.

---

<div class="post-metadata">

**Author:** ![TJ\_V](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/tj_v/32/1008648_2.png) [@TJ\_V](https://forums.unrealengine.com/u/TJ_V)\
**Post date:** [September 2, 2016, 7:07pm UTC](https://forums.unrealengine.com/t/character-collision-physics-weird-behaviour-crouch-uncrouch/368726/2 "2016-09-02T19:07:03Z")

</div>

Hey NewWrench,

Enabling ‘Use Flat Base for Floor Checks’ drastically fixes the issue for me. How did you implement your crouching mechanic? I’m setting the Capsule Half Height to 60 on crouch then back to 96 on uncrouch.

You could also adjust the Perch Radius Threshold in the CharacterMovement component and keep the player from standing on the edge of the physics object all together.

To fix the ‘standing on small physics object’ issue, go to the CharacterMovement component of your character. In the Details panel \> Character Movement: Physics Interaction \> Lower the ‘Standing Downward Force Scale’ value.

---

<div class="post-metadata">

**Author:** ![Wrenge](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Wrenge](https://forums.unrealengine.com/u/Wrenge)\
**Post date:** [September 3, 2016, 7:37pm UTC](https://forums.unrealengine.com/t/character-collision-physics-weird-behaviour-crouch-uncrouch/368726/3 "2016-09-03T19:37:36Z")

</div>

I implemented it via CharacterMovementComponent’s bWantsToCrouch variable. Did I do it wrong?

Small physics object issue has been resolved by itself for some reason.

---

<div class="post-metadata">

**Author:** ![TJ\_V](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/tj_v/32/1008648_2.png) [@TJ\_V](https://forums.unrealengine.com/u/TJ_V)\
**Post date:** [September 7, 2016, 1:10pm UTC](https://forums.unrealengine.com/t/character-collision-physics-weird-behaviour-crouch-uncrouch/368726/4 "2016-09-07T13:10:12Z")

</div>

I’m glad the small physics object issue resolved for you.

But no, that implementation should also work. It’s odd that ‘Use Flat Base for Floor Checks’ fixes the issue with the setup I described but not with the other. I’ve created [JIRA UE-35652](https://issues.unrealengine.com/issue/UE-35652) and our developers will be investigating further. That link goes to the public bug tracker and you can monitor the JIRAs progress.

Cheers,

TJ